make sure the filters are established before you get the fish.
Monitor the fish for a few days before you buy them if possible. Angelfish can carry a virus that kills them very quickly. If they are ok in the shop for a few days and there are no problems, then grab some.
Feed them a varied diet including frozen prawn, fish, brineshrimp, etc. Just defrost the food first. Feed them frozen foods at least twice a week, but preferably every day if you want them to grow and start breeding.
Have a spare tank ready for any fish that is being picked on by the others. Sometimes a pair will take over the tank and bully the others. If this happens either move the pair into another tank that has an established filter, or moved the fish that is being bullied. Normally you take the established pair of fish out, leaving the others behind to form new pairs.
Do regular partial water changes and keep the temperature about 24-28C. Try the lower temperature for a bit then increase it to 28C. Quite often that will stimulate breeding activity.
If they do breed don't expect the first couple of batches to survive. Most angelfish eat the eggs and fry the first few times. Gradually they learn not to and then they start looking after their eggs & young properly.