Start with less weight and begin with machines and then slowly get back to free weights.
Three exercises which you should NEVER do because they fu#k your shoulders:
1. Lat pulldowns/Chinups/Presses behind the neck.
2. Upright row
3. Flies (If your shoulders are fine, then it is okay, but avoid this if yoy have shoulder problems).
The best way to avoid further dislocations (called recurrent shoulder dislocation) is to have strong deltoid muscles, following lightweight and free hand exercises is going be of great help.
1. Push-ups or dips
2. Shoulder flies
3. Shoulder front raise
P.S: For all exercises requiring weights, first use Thera-Bands and then opt for dumbbell or other equipment.