The two trimmers on the main board get left alone? thanx
The right hand trimmer on the main board is the one that controls the OD channel level and is the one you'll experiment with most. The PI trimmer (left hand end of main board) is set and forget The trimmer on the satellite board that contains the FET, controls the level for that input. Most owners don't use the FET input much but you might want to just set it to a sensible level and leave it, I have mine at 9 o'clock.
Also I noticed I was sent two black an one red bias ports. The drawing shows it in reverse.
That won't matter, just use the red one in the centre. They are just measuring points.
Is the star ground one of the PT bolts or seperate. Pic looks seperate.
Separate bolt with 3 or 4 solder tags. Don't tighten it up until all your joints are made. It works as a big heat sink if you do and a low power iron will struggle.
HTH