You can add backing tracks to your exercises in the SongCreator. You can use your publicly available direct links to sound files, as well as cloud services such as SoundCloud, Dropbox, and GoogleDrive. You can also use your Youtube video as backing track by simply pasting a direct link to the specific video you want to use.
In order to start streaming a track, go to the relevant website/cloud service, and copy the HTTP link for the track. Note: If you're using Soundcloud to upload the backing track, make sure the end of the link is the name of the song you want to upload. here's a good example:
Go to the Yousician SongCreator either by creating, uploading, or editing the song you would like to add the backing track to. Paste or type the link to the text box in the top pane and click on the tick button.
You will briefly see a "download" screen while the song is buffered from the cloud service or server. When the track is ready to be played back in Yousician, you will see the waveform of the audio track on the bottom of the tab staff.
When the waveform is rendered, you will see that the playback starts right from the beginning of the exercise. If the audio begins right away from the first measure of the exercise, and if you have the tempo correct, the audio would be synchronised to the exercise. However, in reality, most tracks begin slightly later, and have small tempo variations, which makes it necessary to have an alignment between the audio and the exercise. In order to do that, make sure you have the exercise data (i.e., the notes) already typed in; you can either enter the notes in the SongCreator, or enter them beforehand using a third-party tool and upload to Yousician. When you have the exercise and the backing track ready, click "sync" on the top pane and choose "Automatic" to automatically synchronise the two. When the alignment is done, you will see that the waveform moves to the correct place in relation to the notes.
If you are not happy with the Automatic synchronisation of the sound, it is also possible to edit the synchronisation manually by moving the whole backing track. In order to do that, open the "sync" menu from the top pane, and toggle on "manual". When the backing track waveform turns green, you can drag the waveform to fit the exercise. To get the best results, make sure that the exercise is in the same tempo as the backing track.
To check the synchronisation, click "play" to listen to your track.
Similarly, you can also create a copy of an existing song and replace the backing track following these steps.