I am new to Blender and have been using it only for a week but have been making good progress. I’m mostly interested in using it to develop files for 3D printing. One issue I have been having is as follows. For example, if I start off with a cube that is 10cm x 10cm x 10cm, how do I create a new edge 2cm in from one of the sides? In SketchUp I used the ruler to slide along an edge to create a specific point so that I could draw another edge from it. I have tried selecting a vertex and extruding along an edge while constraining to the appropriate axis so that I would have a vertex to snap to later but I have a hunch this may not be a good way of creating my model as I am basically creating edges over the top of other edges.
I have attached an image to give a better idea of what I mean. Hopefully this makes sense and someone can point me in an appropriate direction.