Hello Gerlinde

Categories are where your services can be sorted.

For example, if you have "Music", "Sports", "Math" categories, in "Music" category, you can have services like "Guitar Lessons", "Violin Lessons", "Piano Lessons"; then in "Sports", you can have services like "Basketball", "Football", "Tennis" and in "Math", you can have services like "Algebra", "Trigonometry", "Geometry", and so on.

Every Service needs to have a duration, and that duration (+ any buffer times you may add before or after service) is used for appointments. So, one service can have multiple employees assigned to it, and every service can be covered by an appointment at the same time for as many times as there are employees assigned to that service.

Events should be treated like presentations or concerts. You choose when it's going to take place, and for how long, and whether there's going to be an employee (staff) assigned to that service or not. An event can be held across multiple days, or it can be recurring.

Tags are added when you're creating an event. Simply click on the Tag field, and enter tags.

That's right, Gerlinde

The only connection between them would be if you assign the same employee you have assigned to a Service, to an event (as staff). If you do that, the employee will not be able to accept any appointments for his services until the Event is ongoing.