Orphaned kitty questions?

two days ago i found a little male kitten in the street alone crying so i took him home, i believe he is 3 or 4 weeks old..at first i didnt have KMR so i gave him cow milk because he was crying a lot..know i've bought him KMR and i bottle feed him at least every two hours.. and i also make him pee .. last night he pooped and his poo came out fine( i was worried about the poo because of the cow milk) anw this morning he woke up crying i feed him played with him and put him to sleep but he woke up after one hour wanting to eat again so i fed him cause he wouldnt stop crying know he is sleeping.. also at night i dont feed him because he is sleeping and i have to sleep to.. can that cause any problemss?? i want more info for how to take care of him and i dont know how much milk i have to feed him..