Need help with japanese phrases !?

Question

what's the difference between

nemuri ni tsuite

and

nemuri ni tsuita

thank you!

Answer 1

nemuri ni tsuite

=fell asleep and ___

nemuri ni tsuita

=fell asleep

Answer 2

the first one is conjunction form, so it's "fell/falling asleep and then..."

the second one is past tense: "fell asleep"

Answer 3

the bottom is past tense  

Answer 4

tsuite= progressive usually, te form is like "gerund" tense.

tsuita= past tense. Already happened.

Nemuri ni tsuite= falling alseep

Nemuri ni tsuita= fell asleep