Hello,
about the sorting duel, ctrl+a number, followed by ctrl+another number will swap the places of those two notes.
For example, if we have 1=C, 2=e and 3=d, and you press ctrl+2 followed by ctrl+3, 3 and 2 will swap their places, so 2 becomes d and 3 becomes e, and you will also hear the two notes that you just swapped.
In the colored buttons duel, this works differently.
Every button has one of two colors, signified by a sound. If you press a button, for example 5, this will change the colour of that button, but also of its neighbours (adjacent buttons). Meaning that in this case, it will swap 5, 4 (since it is one to the left of 5), and 6 (one to the right of 5).
So in this duel, there is no need to press two buttons before something happens.
In case you played Crazy party, this is basically more or less a mini simulation of the colored buttons game.
Hopefully that helps, and feel free to ask any other questions without worrying if they were asked before, that's the purpose of the forum :).