Title: my present
I do today homework.
Simultaneously i drink water.
Water is lukewarm.
Do you study in the dormitory restaurant
Yes I do, I study in restaurant because here is a little quit.

Corrections:

I do today homework.
Simultaneously i drink water.
Water is lukewarm.
Do you study in the dormitory restaurant
Yes I do, I study in restaurant because here is a little quit.

I did my homework today while simultanesouly drinking water. The water is lukewarm. 

Do you study in the dormitory restaurant?
Yes I do, I study in the restaurant because it is a little quiet here.

You have very minimal corrections. I just corrected the construction and the tenses. Good job!