How do you machine tie a quilt?

You just go over the last stitch back and forth for a few seconds, this makes it sturdy enough to hold. if you like you can do the same over the first stitch.

To tie a quilt by hand, you go to each point where four squares meet and place a piece of yarn/thread that you then tie. To do this by machine, you would place each intersection under the needle, sew an x, then pull enough thread out to tie a knot by hand.