First let me say we are not experts at all. Probably we have just been really lucky. But here is what we did:
This article was a starting point -
http://www.brineshrimpdirect.com/c90/Raising-Live-Rotifers-Copepods-c199.html
We happened to have a 5 gallon tank in a closet which we used instead of a bucket.
We started with the tank about 1/3 full of saltwater, the same salinity and temp as our display. Other equipment includes an air stone, a light (because we had one, apparently not necessary) and a heater (the room the tank is in gets quite cold in winter.) We added a bottle of tigger pods purchased at the LFS and enough live phytoplankton (we use DT live phytoplankton) to make the water green.
I top off the water by eye with fresh water. When a lot of foam forms or when the water starts to smell funky I add salt water to dilute the waste. Once I've added so much water the tank is full I do a large water change. In about 3 months we've only had to do that twice.
All the water is RODI.
For feeding I add a small amount of phytoplankton daily (to keep the water green but not opaque).
After about a month there was a visible "explosion" in the population so we began harvesting them daily.
To harvest we use sieves. This is also how we do the water change - the water being discharged is run through a sieve to retain the pods which are returned to the tank once the fresh saltwater is added.
We have a lot of pods despite harvesting some daily. Our mandarin visibly gained weight with the feeding. He had been rather thin, now is almost plump.
There may be things we should be doing that we aren't, this is our first go at it and so far so good. If others have more reliable methods their advice may be better. We are novices.
It doesn't cost much to set up. Sure is worth a try if you have a mandarin.