I configured everything for the reservation, but there is one option missing that I can not find.
In the setup of the services I fixed a max of Seats which can be booked (3 in my case)
When the customer makes a checkout I want the names for all the seats of every person.
e.g. If the customer choose 1 seat I will ask his name, mail adress etc.
if the customer choose 3 seats I want the 3 names of these persons and their adress etc.