It'd help if we had a bit more info on what's tripping you up, gi. Most emulators are fairly simple; download, uncompress, run program, open game image (usually a rom or cd and via a very simple "open rom/cd image" command in the menu), play away.
As for USB, I usually play emulated stuff with the keyboard, not a controller, if that's the concern. You can use non-console controllers just fine, though.
Later edit: If you're asking how to manually dump rom images from an SNES, that... that's a bit more involved. Pretty sure it takes special adapters and more technical knowhow than I've ever had. I can probably hunt up some tutorials somewhere, though, if you're trying to pursue that.
Later later edit: SNES9x runs the SNES der langrisser recently translated just fine (or it did for me; going by the patch read me, this is likely because I disable sound), so you're not stuck with bsnes (which is a freaking terrible resource hog, for all of it's accuracy). 9x is also a bit more user friendly. There's also a workaround for ZSNES.
Lunar IPS is also a much more (windows) user friendly patching program. Byuu's patch does take a UPS patcher, though, so go with upset. Forget what I used, eh.