Aim for between 8-12 reps on each exercise, and 3-5 sets.
TOTAL working sets during your workout will lead to muscle gains, therefore you need to spread your sets out across a varying number of exercises.
For big muscles groups such as chest/back/legs, aim for 15-20 TOTAL working sets PER MUSCLE GROUP.
For small muscle groups such as biceps and triceps, aim for between 8-10 TOTAL working sets PER MUSCLE GROUP.
These numbers may vary if you respond better to HIGH VOLUME training, meaning you would need to do more sets for big and small muscle groups.