Was out on kr1-s bike and now know just how crap my back brake is. I got another used/good back disk (old was screwed) and some new back pads. I took off caliper bolts and removed old pads.. what ive discovered and probably the reason for the back brake being so crap is one of the pistons was jammed solid with rust/crap (bike never ran for years) I disconnected caliper from brake line and put caliper in a vice.. got the stuck piston to move and now its fully in again. Basically I want to make sure the pistons are moving proper before putting pads in. I reconnected brake line but now when back brake pedal is pushed the pistons dont move at all (not even the one that was free) I assume its full of air now and needs bleeding.. been looking at my caliper and manual and they look different.. I have uploaded my pic (bit blurry) here ..

To me it doesnt really have them 2 bits at manual or at least it looks different. Im thinking maybe T3 in manual pic below is actually the screw in my pic above ? ?

Now im wondering how to bleed the thing.. what is that screw in my caliper and what is that rubber bit for ? Behind/inside that rubber bit is just solid metal. Any idea ?
Thanks