What’s your goal in building your own light? Are you doing it for the learning experience?
As @INeedMoreLumens said, you should start with choosing an emitter as that will narrow down the driver options.
You need to decide what kind of light you’re looking for. Floody, balanced, or throwy beam? What CCT? Do you care about CRI?
No offence, but you’re not going to learn very much from us telling you what LED and driver to get. Your build will amount to soldering two wires and then you’re done. We can offer recommendations but we need more info about what you want.
Perhaps you should do some more research on LEDs and drivers. Here’s good info in LEDs:
Are you wanting to order everything from Mtn? That’s fine but their options are a little dated.