Simple workouts using dumbells for beginners.
Pushups = 3 Sets × 12 reps
Floor chest press= 3 Sets × 12 reps
Bridge chest press= 3 Sets × 12 reps
Chest flies= 3 Sets × 12 reps
Overhead dumbell extension = 3 Sets ×12 reps
Closed grip pushups= 3 Sets ×12 reps
Kickbacks = 3 Sets ×12 reps
Chair dips= 3 Sets ×12 reps
You can also increase the weights for every set and reduce the number of reps.
Or u can have standard weight and follow the above reps.
To build a bigger muscle keep pushing more weights and never give up.