Hello AOTR and welcome to the forum.
Best way to keep a small colony is in a test tube. You can keep them there until they have +- 100 workers. Connect the tube to an out world where you can feed them. If the colony gets to big for the tube you can move them to a setup.
There is a lot of information here at the forum about keeping ants, read a bit and use the search engine, if you still have questions later feel free to ask.

Good luck.