Serpentine belt

I have a 99 nissan altima and my friend replaced the serpentine belt after it fell off. The car is still chugging when I accelerate. Does he need to time the serpentine belt or any ideas what could be wrong?

You need to clarify a lot of things.
Car chugging before the belt change I assume?
Sepentine belt or timing belt?
Check Engine Light on, or ever was on?
Why did this belt, serpentine or timing, fall off? Snapped in two or what?

It’s difficult to help with no info provided.

Troll, OK? Never came back.

Seems to be the norm at times, unfortunately.