The best way to build muscle is to work out for 30-60 minutes 3-5 times a week and vary your routine every month so you don't plateau.
To build your back muscles, do bent-over rows and pull-ups.
To grow your pecs, do push-ups and lift weights on a bench press.
Work your shoulders with overhead presses.
Target your leg muscles with deadlifts and squats, and build your biceps and triceps with arm curls and dips.
Finally, do planks and crunches to build your abdominal muscles