As a newcomer to CAD drawing I'm having some problems getting the hang of how things work (despite having studied the manual).

Why are the units set to inches when I choose "architectural" in setting unit scales? How do I change to metric?

Where do I set the drawing scale, e.g. 1:100, 1:200 etc?

When I insert a dimension, the displayed result is not exactly as the reality, e.g. I have a line with a length of 94mm (this is how I created the line and how it shows in the property menu), however in doing the linear dimension command via "entity" the result is 90.39. How is that possible?

I'm sure more questions will arise as I progress!