This is simple, but I messed it up a few times while learning. Basically, to grab the coin and reset warp, you want to look at the coin so that it is outlined in white, pause, click "restart level", and then press E (or spam like I do). Note: You do not pick up the coin before you pause, OR as you pause. A couple of things I tried that didn't work when trying to learn it were: picking up the coin, then resetting, pressing E to pick up the coin at the same time I paused, or pause, pick up the coin, and then reset. All of those will fail.

TL:DR Hover over coin, pause, press "restart level", press E to pick up IN THAT ORDER