Hi Jesset, happy to help!
Washington says that he takes the future of the nation seriously, and while conscious of his own flaws, he hopes his advice will help contribute to building the best system of government possible.
In the discharge of this trust, I will only say that I have, with good intentions, contributed towards the organization and administration of the government the best exertions of which a very fallible judgment was capable.
He then continues on to give his advice for the nation. He says that the constitution should be "maintained," meaning that the country should abide by it. Washington adds the importance of "wisdom and virtue," or logic and ethics, among those in government.
... that the free Constitution, which is the work of your hands, may be sacredly maintained; that its administration in every department may be stamped with wisdom and virtue
Washington says that the country must have a government which works for all people across the nation despite "geographical discriminations" and differences between regions.
...a government for the whole is indispensable. No alliance, however strict, between the parts can be an adequate substitute; they must inevitably experience the infractions and interruptions which all alliances in all times have experienced.
He says that the Constitution can be "alter[ed]," but at the same time, unless it is changed people must obey it as law and those who obstruct it must be stopped.
The basis of our political systems is the right of the people to make and to alter their constitutions of government. But the Constitution which at any time exists, till changed by an explicit and authentic act of the whole people, is sacredly obligatory upon all.
In addition, Washington cautions against political parties, setting that they cause division and serve their own interests over that of the nation as a whole. He says that formation of parties is natural, hut can create "despotism" and lead to power in the hands of an individual rather than the nation.
They serve to organize faction, to give it an artificial and extraordinary force; to put, in the place of the delegated will of the nation the will of a party, often a small but artful and enterprising minority of the community;
I have already intimated to you the danger of parties in the State, with particular reference to the founding of them on geographical discriminations. Let me now take a more comprehensive view, and warn you in the most solemn manner against the baneful effects of the spirit of party generally...The alternate domination of one faction over another, sharpened by the spirit of revenge, natural to party dissension, which in different ages and countries has perpetrated the most horrid enormities, is itself a frightful despotism. But this leads at length to a more formal and permanent despotism.
Hope this helps!