I have been [STRIKE]told[/STRIKE] given a few exercises by the doctors. I have to perform them twice a day. Is it correct to say "I perform those exercises every day" or "I exercise every day how I have been told by the doctors"?
"I perform those exercises [twice] every day" is correct.
"I exercise every day how I have been told by the doctors" is not.
"Twice a day, I do the exercises the doctors gave me" is how I would write your longer sentence.
You still need to work on the difference between "few" and "a few".