First time Biasing tubes

Don't freak out.
The high voltages are inside the box.
There's nothing to be affraid of arround the bias probes as you will measure there only milivolts.
275mV in triode or 290mV in ultra-linear modes.

In some of VTL models there's one extra bias pot which is called Master Bias that regulates the bias current on all of the tubes.
In some tube models designers would place an extra bias pot onto each PP pair of tubes to adjust them both and each one independedly.
The red color leads on your voltmeter should touch the bias slots and the black color lead should touch the ground or chassis. You may also connect the black color lead onto your ground binding post.

No it's NOT right!
Bias slots are ONLY for the RED lead of your voltmeter.
The black ground lead of your voltmeter should be connected to chassis or ground speaker binding post.
RIGHT and LEFT mards I assume are for master bias controlls for each CHANNEL to add more flexibility towards using unmatched tubes.
I'm not familiar with Scott amp and telling you from the general tube experience and knowlege of a major tube circuitries.
You should also know what bias level you should set according to manuals. You should use a milliVolt scale on your voltmeter if it's not digital with auto range.
Slowly vary the trim pots in order not to over or underbias too much.