Power saws go out of alignment through the vibration that accompanies use. Also, radial arm saws do not like to be moved, and settings will probably drift when one is moved. But, a lot depends on how much precision the user is looking to have from his saw. If you plan to use the saw only to cut 2 x 4s to length, the accuracy you need is not the same as if you were doing fine cabinetmaking with the saw.
Step 1: Assemble the stand
I like to have my saw away from the wall. For one thing, this allows me to hang blades and other fixtures on the back of the saw stand. It also allows me to walk around to the back of the saw rather than reach over the table for some set up and service procedures. And, I want to be able to put pieces of lumber eight feet long onto the table and take them off of the table from both sides of the saw. Workshop space is somewhat limited. Moving the saw out from the wall allows me to pass lumber in front of my workbench when things like my vise would otherwise obstruct.