Here is a way to define arms and back with free weights.
Complete this circuit 2-3 times – each exercise 10-12 reps
EXERCISE MUSCLE WORKED
1. Seated shoulder press shoulders
3. Double back row lats
4. Lateral raise shoulders
5. Seated reverse fly rhomboids, traps, lats
Make sure you are using enough weight to challenge your muscles by the last rep .You should really be feeling the burn in order for your muscles to change.