If you're looking on how to make simple key chords, you can do them with advanced triggers. For example, "Hold the middle mouse button + right click to move right a space" with a normal mouse:
- Go to the normal mouse triggers
- Create a new trigger, in the key, put the right mouse button
- Go to the "advanced" tab and open "advanced conditions"
- Delete all the conditions in the board but one
- Change the condition to "current_pressed_mouse_buttons" and in the value put "1,2," (notice the extra comma)
- You can see the value of this variable on the right side
- Give it a test by pressing the middle and the right mouse buttons, the container should turn green
- Click ok
- Make sure the trigger conditions are "on mouse down" the repeat option is disabled and you can move the mouse during the chord