What is eartraining?
Eartraining is, among other things, about understanding what one hears in music. Is it major or minor, strong or weak, many or few instruments? It is a good place to start, but the eartraining is also very much about reading and understanding rhythms and notes, hearing intervals (distance between tones) and more. It’s about combining sheet music / theory with what you hear to become a more confident musician. The reading of sheet music is improved, and it is easier to understand how the music is structured.
Once you have gotten through the beginner’s material, there will be exercises with music dictation (write a melody down on notes by listening to it), rhythm dictation (write a rhythm down on notes by listening to it), correction (find errors in the notes when you listen to the music). There are many other things such as singing from sheet music and more.
Even if you have been playing for a year or two, it is a good idea to start with the beginner tasks, as you will then learn how to tackle the more difficult tasks.