How do i sign up for Philadelphia housing?

Im a 19 year old student who is currently homeless. I was wondering how do i sign up for housing so that i would be able to have a place to stay for the holidays. I was in foster care but i aged out so im just on my own right now. My home is really my dorms and where ever i go for the holidays. I just need to know how to sign up for these things so i can get an apartment for my self because my living situation has gotten ridiculous. Could someone give me links or websites how i can sign up online or get help. or please explain to me what i should do because i wasn't taught these things but im mature for my age i understand well when it comes to things like that.