I know the formula, but I am having a hard time putting the formula for finding compound interest to use.

Principal = $5000
Rate = 7%
Time = 6 yrs.

I have to find the interest after semiannually, quarterly, and monthly.

Can someone help me and also break down how it's done?

http://math.ucsd.edu/~wgarner/math4c/textbook/chapter4/compoundinterest.htm

examples of daily, weekly, monthly, quarterly, annually in there

You have to figure out how much interest you have after each period? Or after the 6 years under each compounding criteria?

Do you still need this?

semiannual n will be 12, i/y will be 7/2
quarterly n is 24 i/y is 7/4
monthly n is 72, /y 7/12

5000=pv
comp fv

Just divide to annual interest rate by the number of periods
aka 0.07/4 for quarterly, 0.07/12 for monthly...