Hi Justin,
For translations:
Qui = who for person and which for non persons, also whom, also whoever (anybody).
This expression is interesting, as 1968 Larousse translates it by "qui que ce soit", which is true.
Que, in this same pockey dictionary, is whom, which, what, that, as and than.
So que is wider than qui.
Mainly is what the three persons above wrote, que is for things or non-persons (animals), qui is for persons, people.
Now in the French Petit Robert dictionnary of 1993 and 2011 grand Larousse encyclopédique :
Qui = pronoun.
Que = conjonction.
This is grammar, if you want we can speak about that tonight, mainly, conjonctions are linking words, pro nouns are for nouns, as their name says, they remplace the name(s).