1.Find F3 below middle C.
2.Locate the string and follow it to its tuning pin.
3.Put the tuning lever on the tuning pin.
4.Adjust pitch down. You should hear it change. If you do not hear a change you may be on the wrong pin.
5.Tune F3 as a perfect 5th to C4.
6.Tune F3 as a perfect 4th to Bb3.
7.Tune F3 as a pure 3rd to A3.
8.Repeat with various beat rates for the 5th, 4ths, and 3rds.
9.Tune the unison to put things back the way they were.
Pure intervals have no beats. You should be able to temper 4ths and 5ths to have 1/2, 1, or 2 beats per second. You should be able to temper 3rds to have 0,2,3,4,5,6,7 beats per second. Remember 3rds and 4ths are tempered wide and 5ths are tempered narrow.
Alway remember to PLAY THE NOTE WHILE YOU MOVE THE PIN!