Group reservations can be entered on Calendar or on Reservations overview. Since both are the same, we will explain how to enter reservations via Calendar.
Above the Calendar itself there is a button "+ group reservation".

By selecting it a pop-up window will appear, where you will:

Once you have saved the group reservation, the selected units will be marked as reserved in calendar and they will all have an automatically generated tag (e.g. G4).

By clicking on any of the reservations, a window will pop up showing reservation details and standard options of a single reservation as well as the options to edit group, create a group invoice or cancel the group reservation.

Changing guest names in the group
In order to change the names of guests belonging to a specific group, you can edit individually each reservation you open on the calendar or edit group details.

There is a simple way to Copy a group holder / booker to one individual reservation.

Once all the guest names are changed, save the group reservation and the names on all reservations belonging to that group will be updated. 

Creating a group invoice
A group invoice is issued almost the same way as a regular reservation invoice. Clicking on any reservation that belongs to the group will open a popup window with details and options. Selecting Group invoice opens up an invoice draft with items containing all reservations belonging to the group. Selecting Issue in the bottom left corner confirms creation of the invoice.

If you want to charge one reservation separately from the group, you can easily create an invoice by selecting that reservation in the calendar and clicking on Invoice. A draft invoice will pop up and the procedure is the same as with regular individual reservations. However, when you want to issue a group invoice, it is important to remove that reservation from the item list in the group invoice draft. You can do so by clicking on the trash bin next to the item.