IMO, they are the easiest fish to breed. Basically, if you have 2 of them in a tank, they'll eventually pair up and start breeding.
My suggestion is to look for a large clown and 2 smaller ones. I like to get them from different sources to ensure they're not from the same clutch (i.e. they're not related). They'll spend some time shaking and shimming at each other until they sort out who's the boss. Eventually you'll end up with a pair. You can also just do this with two, or look for a pair locally. I find many people locally selling mated pairs for various reasons.
You will need to maintain a stress free environment and good water parameters before they'll start to breed. After a move, a breeding pair may take several months to get back in the "groove". And a healthy diet is important to.
It's also best to set them up in their own tank with no distractions. A 10g bare bottom tank works for occy's. I used drilled tanks and ran them with a sump. Place a few flat tiles in the breeding tank to make egg removal easy and hatch the eggs in their own separate 5ga tank (cycled with a sponge filter). Once they lay the eggs, remove the tile and replace it with a new one. The clownfish will lay another clutch usually within a week.
You'll have to get good at culturing rotifers to raise the babies. Reed Mariculture is the place to get phyto and rots. I here some people are using a small copepod breed instead of rots with success. I'll ahve to find the name. But rotifers are tried and true method.
The biggest problems is waiting for them to start breeding. It can takes 6 months or more. Even with a know mated pairs.