I want 2 lose weight and build muscle

I was wondering whats the best exercise to burn fat? i am overweight but found out in the past when i exercise and eat healthy i lose weight fast. also i have weights and want 2 no whats the best way 2 help build muscle in like my arms? im eatin healthy atm tho not losin w8 because im not exercisin tho if i exercise daily i cud lose w8 fast. if any1 could reply 2 this i'd be extremely grateful thank you