I struggled with scheduling the charge timer issue for several weeks as well but finally I think I have it right as far as creating a schedule that only charges between certain times, in my case, between 10:00 pm and 5:00 am. I found the manual poorly written in this regard and our dealer set the charging schedule but didn't quite get it right either because it started charging immediately when first plugged in instead of waiting for the appropriate time.
The key to understanding the Audi scheduling system is understanding "Departure Time". When you are setting a charging schedule, the system is asking you "what time do you want the car to be ready to go?" That's "Departure Time". So if I want to leave at 6:00 in the morning, my charging needs to be done by that time. So you set the Departure Time first. Then you add the earliest time charging should begin which in my case is 10:00 pm.
If you're using the Audi app, you can see your schedule by clicking on the charging icon under Your myAudi connection services. When you click on that icon, you get 3 tabs at the top "Charging Timer and Charging locations. Click on Timer and you'll see the 5 charging options for Departure Time. In my case the first tab says 5:00 AM Daily and the tab is highlighted black. Then click Charging locations and you should see the Charging schedule you've created under "Preferred Charging time". Mine says 10:00PM - 5:00AM. If you click the arrow button then you get to your charging location screen which in my case is my home address. The final step is to De-activate the "Activate 25% minimum charge". It's this button that automatically starts a charge every time you plug a charger in, regardless of whether your timer schedule says to start at a later time.
Once I de-activated that setting and plugged the cable into the charge port, the car flashed white to connect and then started blinking green rapidly. Also, my Audi app then told me charging was waiting to start. To see how this really worked, at 10:00 that evening I checked my Audi app and charging had not started because my estimated charging time to reach 80% was only 2+ hours. The next morning I was up early and at about 4:45 am, my Audi app showed charging was active and at about 76% capacity. Promptly at 5:00 am, charging stopped and my Audi app showed that the charging was complete.
Sunday I plugged the car in the afternoon because weekends are different for rates and I didn't care if it started charging right away. To allow it to charge right away, I clicked off the schedule under the Timer setting and the car started charging as soon as I plugged it in.
While writing this post, I've noticed in the app that the "Activate 25% minimum charge" setting is on again. I intend to charge tonight when I get home so I've disabled that setting and when I plug the cable in tonight, my timer setting will kick in to start between 10:00 pm and 5:00 am. Apologies for the long winded post but this issue was very confusing to understand.