Hi, yes it's the minimum charge setting. It means that if you set a departure time it will charge to up to the level at which you set that slider bar (in your case it is set to 0% so won't do anything).
The maximum setting is 50%. So if you set a departure time for tomorrow with it set at 50% and your battery level is at 30% it will start charging immediately until it reaches 50% then switch off and will restart later to fully charge prior to your departure time.