After looking at pictures online of a number of other people's projects, I identified a couple must-haves for my own:
-Freestanding : I was planning to move, didn't want to make holes in the wall that I'd have to turn around and patch, and I couldn't be sure my next place would allow wall-mounting.
-Collapsible : I was sharing a one-bedroom with my partner, and we wanted the treadmill belt to be able to fold up when I wasn't using it to free up the space.
Step 1: Get a treadmill
Through lucky timing, I connected with a collapsible treadmill owner who in the process of decluttering.
Not all treadmills are collapsible, so I specified in my ad that I wanted a collapsible one, and verified this detail with people who responded to my ad before going any further. Before picking up the treadmill I was ready to accept, I also asked the owner to send measurements to verify it would fit in the small space available to me.