I looked at the photo on the website link given above, and if you enlarge it and look closely you can see which two are the locking casters. They have the little knob on them, which in the picture is down, because they are locked. They are on opposite corners of the legs of the main table, not the fold out legs. (Back right leg and front left leg, or vice versa).
Last edited by JustAbitCrazy; 02-10-2019 at 03:22 PM.