The diagram is a screenshot straight from the Mesa TC50 manual. The "User Memory/Preset Number" column is MIDI PC# for that specific combination. The "0's" are what is turned on for if you use any of the #'s in the PC value.
For example:
If you want just Channel 1 on the amp, no FX loop, Reverb, or Solo functions on, you can use the PC# 1, 16, 31, 46, 61, 76, 91, 106, 121, 136, 151, 166, 181, 196, 211, 226, 241, or 256. These are all factory settings that exist in the TC50 already.
If you use a PC# value of "20", it is Channel 1, with the Reverb, and Solo on.
In FX8-Edit under the "Config" tab then the MIDI PC section, you will see the PC values for each Scene. If you just click the arrows you can watch the amp selection change in real time, try it.
The way I set up my FX8 is with Scenes. For example:
Scene 1: Using PC#17 my amp is on Channel 1 with the effects loop on. I set up the effects on my FX8 to have a Phaser on before the front of the amp, and a Delay on in the effects loop of the amp. As long as I stay on this Scene I can toggle whatever effects on or off I have in the Preset.
I like to press 1 button and have effects turn on or off, and the channel on my amp change. I'm not a big fan of using my FX8 like a bung of pedals and tap dancing to turn them on or off. If I used it that way, I would just have a couple of pedals, and use the amp footswitch that came with my head.
Every Preset will need the PC#'s in the "Config" tab to change the functions on your amp. Fortunately you can copy a Preset to a new slot and have those already done, then just add the effects in the order you want them and start playing.