I think most modules generally include drivers.
But if you're thinking of one of DTR's which just include the diode pressed into the module (yes he does sell ones with drivers, see link), you will have to obtain or build your own driver.
The host you have, what size module will the heatsink fit? Would you have access to some sort of machining tools to make a new heatsink or adapt the one you have to fit? Although, at 50mW for a 445nm it's possible to run the module without a heatsink I think, with a decent enough duty cycle.
Most 445s owned are the multimode 1+W. But there is a single-mode 450nm OSRAM diode at 125mW which DTR sells.
https://sites.google.com/site/dtrlpf/home/diodes/450nm-pl450-diodes
The datasheet says it's an 80mW diode but it looks more than possible to underdrive it so that you'd get about 50mW (some people would say it's a waste of a diode, but why not). In fact DTR probably wouldn't mind doing it for you if you PM'ed him and asked nicely.
When you say 'how do you make sure everything works together to work desirably' what do you mean? Do you mean how do you assemble a driver/how do you fit everything in a host or what? because I think there are stickies in the Host subforums which tell you what the pill and the tailcap and the springs or something are.
I don't know if I've been helpful or the opposite, but it is a fairly involved sort of thing and I reckon I should leave it to the more senior members to help.