The syncing process on SelBuk requieres the cloud service on the plan acquire. So when there is data to be synced it will be uploaded to the cloud service or downloaded to mobile device. However, any existing basket will not be sincronized to the cloud service at all.
When you install SelBuk on your mobile device and there is data to be synced, SelBuk will show this pop-window
When there is not automatic syncing you should do this
Main Menu > More
Sync
Sync now
Now you may set SelBuk to sync automatic at
Main Menu > Settings
Sync activate both syncing buttons