I am borrowing a Homeline 26ss and supposedly you just tap the red bottom on the ground and it will feed out more line. I've "tapped" it on the ground at least 20 times and it still doesn't feed out. I know there is line in there as it is almost brand new and there is about a centimeter of line still sticking out. I've tried tapping it harder and lighter on the ground. Is there something I'm doing wrong or not doing to make this work?

The line sometimes will twist in the spool. Here you will need to remove the spool and untangle the line and sometimes it will disengage from the holding holes in the spool. The difference with this spool nut from all the others I have used, the thread on the nut is left handed thread. In other words instead of turning clockwise you will be going counter clockwise to place it back on.