Exactly what I was looking for

It was not easy to find exactly what I needed. I wanted a solution to generate automated appointment times based on some rules, so my client appointments take place when I want. This plugin did just that. Its easy for my clients and also easy for me. The setup took approx. 10 minutes and everything was set up. There is a PRO version with some neat additional features, but for now the free version also works nicely and without any issues.