Hello,
To load different Programs on the H90, you will need to send Program Change messages from your MIDI controller. Once a MIDI controller is connected to the H90’s MIDI input and you have set all of your devices to use the correct MIDI channels, there is no further configuration necessary. For example, send PC10 from your controller, and it will load Program 10 on the H90.
Sorry, I’m not familiar with the BluGuitar Amp1. You will need to consult that product’s manual for information about the MIDI functionality.