Have you tried Google? There's a whole bunch of stuff if you look for something like "Fusion 360 add tool to library". The Youtube videos by NYC CNC are well-regarded and he has one, I see. It's a pretty straightforward thing to do, once you have found out what the important parameters are as opposed to the ones you can ignore (bit like much of F360, in fact). Ignore things like "toolholder", for example. It's important for some things, but safe to ignore when you're getting started.