What is the equivalent degrees of one "turn"
A turn is 360 degrees. 

You are expected to put a mark on the thing you are turning, so you can observe its rotation.  

They have no way of knowing which kind of wrench you are using, what your wrenching style is, or what amount of swing angle local clearances will afford you. 

"Hand/finger tight" is the point at which all free lash/slop has been removed, further turning actually loads the fastener, and torque becomes measurable. 

In a fastener in tension, how much strain a "turn" amounts to depends an awful lot on the length of the fastener subject to tension. Getting from "strain" to "torque" then involves a lot of other stuff.  

In the case of the anchor in your link, it has little to do with tension.  It is intentionally deforming the anchor to make it engage the hole you just drilled.