I am trying to learn perspective by doing exercises in PS to save paper and take advantage of the quicker workflow, but I am hitting a solid wall when it comes to figuring out how to measure and divide in PS. For example, if I was to draw a cube using pen and paper, and then subdivide the cube so that it had 9 faces on every plane, like a Rubiks cube, I could simply take out my ruler and divide my first line into 3 equal sections and have them converge towards the VP. From there I would just use basic techniques, like those in How to Draw from Scott Robertson, to multiply and divide until I got my desired result.
Essentially I am just looking for a ruler tool to measure my lines so I can divide them evenly and construct the underlay for my drawings and paintings. Is there any such feature in PS? To better illustrate my problem I made a simple image, please see below. Thanks for your time, and please excuse my sloppy writing in the image.