Here is a minimal lesson file:

header {
    module = idtone
    title = "Id tone 3"
    black_keys_weight =  0, 0,    0, 0, 0
    white_keys_weight = 1, 1, 1, 0, 0, 0, 0
}

The 'weight' of a tone tell how big chance is it that the program will select this tone as the next to identify. Think of the weight of a tone as the number of lottery tickets with the name of the tone.

The variable black_keys_weight set the weight of the tones c#, d#, f#, g# and a#, and white_keys_weight will set the weight of the tones c, d, e, f, g, a, b. In the example above, the tones c, d and e get an equal weight of 1, the other tones 0. This mean that the only tones that will be asked for are c, d and e, and that the three tones share the same probability to be selected.