It’s very easy and there should be tutorials around (if not, we can help you). Spad.next will work with Xtouch out of the box, i.e. it will recognize Xtouch rotary knobs and buttons and its 2 different modes. All you have to do is enable MIDI support in Spad’s settings.
Any difficulty is not so much on mapping MSFS functions to Xtouch using Spad. It’s mostly figuring out WHICH these MSFS API functions/events/variables are for each aircraft, which has got nothing to do with either Xtouch or Spad.
Once you have Spad you can download other player’s published profiles who are using Xtouch and you’ll have some sample configurations readily available to experiment with.
ps: Having 2 Xtouch’s and 2 SteamDeck’s (XL and 15), I’m now considering buying a Loupedeck Live at some point. For some reason I like it a trillion times more than Deck+ which I find super overpriced.
I watched Les O’reilly’s excellent video series. Start at the first one or two. It took me a while to build, then refine the use of Spad, and I still tinker, changing functions around or setting conditions for example. e.g. to prevent me accidentally shutting PMDG737 engines down on a runway (very embarrassing in VATSIM), I set conditions in Spad such as 1. sim must be on ground, 2. Probe Heat must be off, 3. Park Brake must be applied. I added probe heat recently to prevent a potential shutdown at the holding point with park brake on, waiting for take-off.
This is all easy to set up, and very useful for ensuring the best out of the aircraft and the sim. Spad is not expensive but is very powerful, gets updated constantly and has a large supporter base. Well worth it, especially combined with peripherals such as X-touch and the like.