I will explain the meaning of this pauri in compliance with Guru Nanak's directive to share knowledge. My explanation is as I understand Japuji Sahib

In Pauri 2 there are three important words Hukam-Hukmee and Hukmii. These word came from Arabic laungage. In ordanary conversation word hukam means" order" Which may be obeyed by one or not., ie a father to son or a judge to defendant, the Hukam is delivered through sound or a writt, faliure to follow that order may have alternatve consiqunses you may be fined,jailed or even face death. Just like Guru Teg Bahadur who defied the Hukum of a judge and gave up his life than to follow the hukum.

The soure of the word Hukam is Huk.

huk is a force of action in the internal and external universe. When the force of the wind attacks a tree the tree does not have much of a choice, it has some built in defenses against wind neverthless enough wind will uproot a tree. That extra wind that uproots a tree is a hukam of the nature for the destriction of that tree, and the tree has no alternative but to uproot. And on the other hand if you are hungry and standing under a tree, with fruits, and wondering how to get it, A " Huka" of wind can bring the fruit to you. The internal world works in the same fashion.

First Stanza - Hukam Rajaii chalana Nanak Likhia Naal

The hukam origanated through the process of rajas will always be carried out and you have no choice but to surrender just like the example above. The word " likhia" stresses the certainty of the event.

In the Vedas and Gurbani, the process is explained in much detail in the Vedas, Every man is a King of his universe, in that he has to make decisions every day, several times a day.
There is one of only two " Tatvas" (components) constitute a decision of action.
"Satva" (purity) Tamas (vein). The decission, a King has to make is, which one of these two to choose in the decission of action . For example its tax time, you may chose to lie (tamas) and gain material wealth the mortal body wants or Tell the truth and provide the etheral wealth your imortal spirt wants.

If you chose satva you have generated a " Guna" and generated A "mana" for repetition. if you chose tamas you have generated "avguna" and a " mana" for the same repetition.

When Guru Gobind singh Said " Dharm binah na raj Chalha hun" he strictly points out to the process of Rajas. In that he has promissed that he will use Dharm ( the process of rajas is part of dharm) when he makes his decissons. The process of rajas should always be surrenderd to the wisdom of the guru, "matha takena" is only a symbol that signifies the surrender of your Rajas process to the Guru, as he is the most qualified king, it has nothing to do with showing respect for the guru surrendering to the guru is showing respect for yourself, that way u can never go wrong with the process.
Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/jap-ji-sahib/314-japji-sahib-pauri-2-a.html

When Guru Gobind Singh said " Raj Karega khalsa" he strictly points out to the process of rajas in that he is saying that he will always chose "satva" Khalas.

Now going back to the stanza. Rajii hukam( processed through Rajas) will always be carried out. The hukam origanated through your gunas will bring you pleasure and joy just like the fruit of the tree mentioned above, hukum orignated through avgunas will eventuly uproot you just like the tree mentioned in the example through the wind of Dukh, depression, fear,cowardnes.
Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/showthread.php?t=314

Accordiing to guna and avguna you will u will feel utum or nitch, or receve greatness (Vadhaii) such a hukum is impossible to deliver via sound or writt it just happens, Just like a judge or a father in the example earlier, and the hukmee ( the source) has no human or any shape that u can beg for mercey as u can do with a judge or a father, there is no process for apeal.

At the end Nanak Says Hukmii ( lots of hukums) awits inside your body only not outside.

The last telling stanza " Nanak hukamii joa bujha hum ko kahai na koi"

I will let you translate this this important stanza by your self.

This stanza should explain the greatness of guru Teg Bahadur.

Inder Pal Singh