I'm almost done but

Hi again, I’m almost my slippers, but I do not want to screw this up.SO my ending says: Break yarn.Thread end through remaining sts.Draw up and fasten securely. Sew side of edges togetther to make toe of slipper for length of ribbing or desired amount. Sew side of back triangle to cast-on sts of sides.

I know this may sound like a walk in the park for some but could some one please explain this to me so I fully understand and I don’t screw this up.
Plus thanks for all the help that everyone has given to me!!

Cut the yarn, leaving a long enough tail, and thread it through the sts on the needle like a drawstring, then pull a bit to make sure it’s closed securely. You can use the rest of the tail for seaming the edges together.