There are soo many ways to do it correctly. Basically all you need is space to grow it, this could be a compartment in your sump, or another tank plumbed into your system, good lighting you'll find plenty of info here on lighting, it could be anything from a home PC bulb to MH lights, water flow most macros enjoy good water flow, and of course some macro algae, I would recommend chaeto, its a fast grower under the right conditions and wont get out of control on you if a piece should make it to your display.