You may only need to use the LSB/MSB values if your synth puts presets in banks or if it can hold more than 127 presets. To get a pgm change for preset 127, you might set PC to 127 and leave MSB/LSB at 0. To get a pgm change for preset 128, you’d set PC to 0 and MSB to 1 (you might even need to set LSB to 1 too). But it will vary from synth to synth.
If presets are in banks of say, 50 then the MSB/LSB values will take care of banks A-0, B-1, C-2 etc. But it will change from synth to synth. (But will surely be covered in the MIDI implementation chart in the manual. )
Happily though, Pyramid will send a PC whenever you turn one of the encoders. So you can just fiddle with the 3 encoders until the synth has landed on the preset you want, then you’re done.