1. Drill a row of two holes, 6 to 12 ins. apart, 1 to 1-1/2 ins. in diameter from the boiler to the last joist space. Keep the holes down about 2 ins. from the sub floor.
2. Start running the tubing from the boiler in the hole closest to the center of the joist space. This is the beginning of the loops.
3. Each joist space that is going to have two tubes in it, will require that you leave a loop of tubing hanging down.
4. Singles should be put side by side, and will require drilling a hole in the opposite end.
5. Work the tubing through the holes to the end of the area to be heated by this  loop and return the end of the tubing back to the boiler through the hole nearest the end of the floor joist.

6. Be careful not to kink the tubing. If you kink the tubing during the installing process, mark it with tape and repair after the tubing is installed.
7. Starting with the last joist space from the boiler, attach the tubing next to the outside joist, first.
8. Now pull the tubing loop too the end of the joist space, and staple the other side up.
9. Go to the next joist space and repeat step # 7.

10. Remember to attach tubing at the end of the loops.