Could someone please help a newbie?

[big_pops]

I am an accountant that purchase an external number pad with a space key. I would like to remap the space key to be tab. I would like this to work for the entire computer, but especially Excel if only one program is possible. The issue I'm having is that the space bar on my main keyboard needs to still be space.

I have been reading for a week and everything has completely gone over my head, so explain like I'm five. I have read about QM keyboard detector, but cannot find any more info than a couple of people saying they used it (whatever it is).

If you could just give me a quick step by step that would be AMAZING!

Thanks!