The main thing with a B/T release is:Your drawlength needs to be dead on or just a shade short to get the full benefit of back tension.Even as much as a 1/4-1/2"long makes good B/T hard to acheive.
Your anchor with this type release is a personal thing (whatever feels comfortable to you)I've seen guys rotate them vertical,some keep them flat,others at around 45 degrees.
I personally draw with the relesae flat,as I get close to my anchor I get my elbow up and in-line with the shaft and rotate release to about 45 degrees then settle in and begin aiming.Once im on the spot I begin the push pull.Push meaning=Push with bow arm directly at the spot.Pull meaning=Pull with back muscles(imagine a wall about 4" behind your elbow)try to take your elbow straight back to touch the wall.
The surprise release is what your after,try not to think about rotating your hand to fire the release (If you think about rotating that may be a sure fire way to learn to punch the Stan and that's not what you want).Let the slight rotation come naturally and from your back muscles not your hand.