The question mark may be missing but this looks like a question to me : 'What are First Principles ?'
The term's meaning has shifted more than a little in the history of Western philosophy but Aristotle's characterisation in 'Posterior Analytics', ch. 2 is a reasonable starting point which gives the, or a, basic, sense of the phrase :
First principles are true
First principles are necessarily true
First principles are indemonstrable - they are not and cannot be deduced from anything else since otherwise the premises from which they are derived would be prior and not the First Principles themselves.
First principles are more certain than anything derived from them - anything derived (deduced) from them can contain errors but first principles are free from any possible error as necessary truths.
An example might be 'If equals are taken from equals, equals remain' ('Post. Anal., 76a). Aristotle would also include the law of excluded middle and the law of non-contradiction ('Metaphysics', 996b). Excluded middle : of two propositions, p and ¬p, one must be true and the other false. So 'p or not-p' : 'p' must be true, or 'not-p' must be true. One or other must be true but both cannot be true. By the law of non-contradiction : ¬p(p and ¬p) (not both p and not-p). In other words, no proposition and its negation can simultaneously be true. (Thanks to Peter J on this.)
Before the waves inundate let me just say that I do not endorse first principles, Aristotle's or others, and I do not commit myself to Aristotle's examples as meeting the requirements of his characterisation of first principles. I am simply trying to convey a first idea of what First Principles are or have traditionally widely taken to be.