Here is also a very simple outline from bbconline.
http://www.bbc.co.uk/religion/religions/sikhism/ritesrituals/gurdwara_1.shtml#h1
Gurdwara
A Gurdwara is the place where Sikhs come together for congregational worship.
The first Gurdwara in the world was built by Guru Nanak in 1521-2 at Kartarpur. There are about 200 Gurdwaras in Britain.
The literal meaning of the Punjabi word Gurdwara is 'the residence of the Guru', or 'the door that leads to the Guru'.
In a modern Gurdwara, the Guru is not a person but the book of Sikh scriptures called the Guru Granth Sahib.
It is the presence of the Guru Granth Sahib that gives the Gurdwara its religious status, so any building containing the book is a Gurdwara.
Although a Gurdwara may be called the residence of the Guru (meaning the residence of God), Sikhs believe that God is present everywhere.
Before the time of Guru Arjan Dev, the place of Sikh religious activities was known as a Dharamsala, which means place of faith.
The purpose of a Gurdwara
* It's a place to learn spiritual wisdom
* It's a place for religious ceremonies
* It's a place where children learn the Sikh faith, ethics, customs, traditions and texts
* A Gurdwara is also a community centre, and offers food, shelter, and companionship to those who need it.
Gurdwaras are managed by a committee of their community.
Inside the Gurdwara
There are no idols, statues, or religious pictures in a Gurdwara, because Sikhs worship only God, and they regard God as having no physical form. Nor are there candles, incense, or bells, or any other ritualistic devices.
The focus of attention, and the only object of reverence in the main hall (or Darbar Sahib) is the book of Sikh scripture, the Guru Granth Sahib, which is treated with the respect that would be given to a human Guru.
The Guru Granth Sahib is kept in a room of its own during the night and carried in procession to the main hall at the start of the day's worship.
The book is placed on a raised platform (Takht or Manji Sahib, meaning "throne") under a canopy (Chanani or Palki), and covered with an expensive cloth when not being read.
During a service a person with a whisk or fan called a Chaur waves it over the Guru Granth Sahib.
Although Sikhs show reverence to the Guru Granth Sahib, their reverence is to its spiritual content (shabad) not the book itself. The book is just the visible manifestation of the shabad.
The four doors
There are four doors into a Gurdwara, known as the Door of Peace, the Door of Livelihood, the Door of Learning and the Door of Grace.
These doors are a symbol that people from all four points of the compass are welcome, and that members of all four castes are equally welcome.
There's always a light on in a Gurdwara, to show that the Guru's Light is always visible and is accessible to everyone at any time.
The free food kitchen, or Langar
Every Gurdwara has a Langar attached to it where food is served to anyone without charge. The term Langar is also used for the communal meal served at the Gurdwaras.
The food served in the Langar must be simple, so as to prevent wealthy congregations turning it into a feast that shows off their superiority.
Although Sikhs are not required to be vegetarian, only vegetarian food is served in the Gurdwaras. This ensures that any visitor to the Gurdwara, whatever the dietary restrictions of their faith, can eat in the Langar.
The meal may include chapati, dal (pulses), vegetables and rice pudding. Fish and eggs are counted as meat and excluded.
Flying the flagn (called Nishan Sahib: admin)
Gurdwaras fly the Sikh flag outside. The flag is orange/yellow and has the Sikh emblem (called khanda: admin) in the middle.
In India many Sikhs visit a Gurdwara before work. In Britain 39% of Sikhs go once a week, and while Sikhs do not regard any particular day of the week as a holy day, they usually go to a Gurdwara on Sundays as that fits the UK pattern of work.
Most Sikhs go to the Gurdwara on Gurpurbs, the festivals honouring the Gurus.
Anyone, of any faith, can visit a Gurdwara and will be made welcome.
Before going into a Gurdwara
All visitors to the Gurdwara should remove remove their shoes and cover their heads before entering the main hall. It is forbidden to smoke or take tobacco on to the premises and visitors cannot enter the Gurdwara while under the influence of alcohol or drugs.
On entering a Gurdwara
Sikhs will bow to the Guru Granth Sahib as the first thing they do, touching the floor with their forehead. This not only shows their respect but also indicates that they submit themselves to the truths contained in the book.
People also place an offering of food or money in front of the Guru Granth Sahib. This is used to run the Gurdwara and the free food kitchen (Langar). The offering is not charity but a sharing of God's gifts. If a person has no money or food to offer they may offer flowers, or just some words of sincere thanks.
After bowing to the Guru Granth Sahib a Sikh will greet the congregation in a low, quiet voice with the words:
Waheguru ji ka Khalsa, sri Waheguru ji ki fateh.
This means
The Khalsa owes allegiance to God, sovereignty belongs to God alone.
Non-Sikh visitors should also bow and make an offering.
Seating in a Gurdwara
Everyone sits on the floor in a Gurdwara. This is to be humble before the Guru Granth Sahib and because it gives everyone a place of equal status to sit. Most people sit cross-legged. Cushions and seats are not allowed.
No-one should sit with their feet pointing at the Guru Granth Sahib. Anyone who walks round the Guru Granth Sahib or the Gurdwara must do so in a clockwise direction.
Men and women generally sit on separate sides of the hall.
Sacred food in the Gurdwara
Towards the end of a service karah prasad, a sweet vegetarian food that has been blessed, will be served. This should be taken and received in cupped hands as a gift of God.
A typical service
Sikhs do not have ordained priests and any Sikh can lead the prayers and recite the scriptures to the congregation.
Each Gurdwara has a Granthi who organises the daily services and reads from the Guru Granth Sahib. A Granthi is not a priest but is the reader/custodian of the Adi Granth. A Granthi must be fluent in reading Gurmukhi and must be properly trained in all aspects of looking after the Guru Granth Sahib. They are expected to be an initiated member of the Sikh Khalsa who lives a life that exemplifies the ideals of the Khalsa.
Sikhs don't have a general official liturgy that must be used in a Gurdwara, although there are rules for particular ceremonies.
Kirtan
The morning service begins with the singing of Asa Di Var, a hymn written by Guru Nanak, founder of Sikhism.
Other hymns from the Guru Granth Sahib are then sung, accompanied by instruments. This hymn-singing is called Kirtan and is an essential part of Sikh worship.
Sermon
A sermon or talk, usually based on a theme from Sikh history, comes next. This is followed by the singing of Anand Sahib, a hymn written by Guru Amar Das, the Third Guru.
Ardas
The congregation then stands with eyes closed facing the Guru Granth Sahib for prayer (Ardas). During the prayer the word Waheguru (Punjabi for 'praise to the Guru') is often repeated.
Hukam
After the prayer, the Guru Granth Sahib is opened at a random page and the hymn found at the top of the left-hand page (Vak or Hukam) is read. The text is considered to be a relevant lesson for the day.
The ceremonial food
After the service, food is offered to the congregation. This consists of Parshad and a more substantial meal in the Langar. Parshad is a sweet made from equal quantities of wheat flour, sugar, and clarified butter.
The first five portions are given to Khalsa members in memory of the Panj Pyares (the first five members of the Khalsa). After that parshad is served to everyone without distinctions of rank or caste.