I have a Monoprice Maker Select v2. I assembled it, but i realized the back ‘sensor’ is too low to touch the bed. this won’t let me hit him or use the print bed, as the machine doesn’t knwo when to stop going backwards. I know that thing has a name, but i don’t know what the piece is called. I recently replaced my Monoprice Maker Select v2 as the first one had some different issues. I am still new to 3d printing, but I didnt see any easy or obvious way to move that thing up at all. Everything is assembled correctly, but sense just doesn’t line up.

Any ideas what to do?

That switch is not intended to hit the print bet itself. It hits the plastic bracket underneath the bed that attaches your bed to the rails.

Turn your printer on its side and slide the bed all the way back (print head at front edge) that microswitch should activate when the hotend is about 1/2 a centimeter from the front edge of the bed.

If that switch activated from the bed edge you’d have a very limited build area.