라는 거 알다

know that it's X

A quoted description "-(이)라는 거" — the fact that something is X — as the object of 알다 "know". Several lines are a speaker asking you to keep something in mind: 알아주시고 "please be aware", 알아두시면 "if you keep it in mind" — I have dehydrated oily skin, so bear that in mind; knowing this earns you bonus points. The rest are plain knowing or finding out: I know you wouldn't have, I came to realise you have to throw it out, did you know it's the six-month mark? Compare 다는 거 알다, which follows a verb; -라는 follows a noun.