Need to know how to adjust water flow and temperature to walk in tub. Think it's a Premier. Can't find schematic.

We need more info than this. What type of valve do you have? Walk in Tubs at Premier Care in Bathing (http://www.premier-bathrooms.com/walk-in-baths/view-all-walk-in-tubs.shtml) Which one do you have?

It doesn't look like any of those in the pictures from your reply unfortunately