Question

Please can you advise how can I assign Fader 1, 2, 3, 4 etc to inputs Mic/Line 13,14,15,16 etc?

Answer 1

It just works the other way round:

Assign the desired Input (analog 13,14,15,16) to the Channels 1,2,3,4 in their Edit/Routing section or use the Digital Patching Screen. ;)