Can u pls describe the schwa sound?

Then study! It must be in your books, right?

Seriously, I suggest you don't study anything. It'll come naturally.

Professor: Tell me, what's schwa like?
You: (completely clueless) [:^)] Uhhh...
Professor: Good!

short 'the' (before a consonant sound)

French le

Oddly enough, a large per centage of unstressed English vowels "reduce to schwa" in rapid speech, including those underlined here. It varies, depending on the person, dialect, speed and other factors of stress in the context.

Since your need is urgent, there's no point in expostulating on the myriad subtleties. I'll give you my simplest version:

The schwa is a short u sound, as in much, and it's always unstressed. It can be spelled as any vowel: ago, item, medicine, potato, upon.

CJ