If you're following a program which has multiple tracks to choose from you can access these by clicking the expand/drop down arrow next to the track name.

Simply choose the track you wish to view and the content in your calendar schedule will switch.

When you open the program it will always default to the track you had last opened/viewed.

If I change tracks, do I lose all my past training notes?

Any entries you had made in any track, such as Personal Records or Notes will be saved and stored against your client account.

If I change tracks, do I start from the beginning again?

No, you will switch on the new track to the same day you are on in the current track.