Just to dial in an amp and cab as close to the sound and feel you're trying to tone match. After the match replace the cab block with the tone match. After doing the tone match you can save it to a user cab location, saving it this way has the advantage of being able to use the cab block EQ controls to fine tune it later. Mini manual for tone matching, was for AFX II but same for AFX III. https://www.fractalaudio.com/downloads/manuals/axe-fx-2/Axe-Fx-II-Tone-Match-Manual.pdf
There’s a lot of good info already written on this. Have you searched the forum? I found over 100 threads when I searched “tonematch”.