Shiela
The instructions are not difficult. If your phone has the composer facility, it is just a matter of typing a long string of numbers and then saving it

My Johnny was a Shoemaker starts like this:

6*9 588 3 2 1 29 2 6 68 7 1*9
1 7** 7 6 6 58 3 2 1 29 2
6 68 7 1*9 1 7** 7 69

(Spaces not entered, just shown to separate the notes)

To get this, you need to find or make the tune, preferably as an abc, and load it into my program.