Testing N75 Valve in relay valve block

I can find tests to check operation of N75 valve but these are all for an individual valve. What checks can be done to check operation of N75 valve when it is inside the sealed relay valve block box (eg. Octavia 2)

Thinking in terms of which terminals should I be applying a 12v across to test?

Which port should I apply pressure/vacuum to ?  and when voltage is applied pressure/vacuum will be diverted from port ? to port ?

Thanks