Please explain using baby steps. I struggle with math. Thanks!

Problem $7-9$ Calculating the Total Cost of a Purchase, the Monthly Payment, and an APR $[$LO$7-2]$

After visiting several automobile dealerships, Richard selects the used car he wants. He likes its $$13,900$ price, but financing through

the dealer is no bargain. He has $$2,500$ cash for a down payment, so he needs an $$11,400$ loan. In shopping at several banks for an

installment loan, he learns that interest on most automobile loans is quoted at add$-$on rates. That is$,$ during the life of the loan, interest

is paid on the full amount borrowed even though a portion of the principal has been paid back. Richard borrows $$11,400$ for a period of

four years at an add$-$on interest rate of $10$ percent.

a$.$ What is the total interest on Richard's loan?

Note: Do not round intermediate calculations. Round your answer to the nearest whole number.

Total interest

b$.$ What is the total cost of the car?

Note: Do not round intermediate calculations. Round your answer to the nearest whole number.

Total cost

c$.$ What is the monthly payment?

Note: Do not round intermediate calculations. Round your answer to the nearest whole number.

Monthly payment

d$.$ What is the annual percentage rate $($APR$)?$

Note: Do not round intermediate calculations. Enter your answer as a percent rounded to $2$ decimal places.

Annual percentage rate