The most important thing to note is that, while everybody will have View access to all conference room calendars, you may not be able to schedule certain conference rooms. Some conference rooms are configured to require an approval to schedule. For those rooms, a request will be sent through the calendar system to the person(s), who can schedule the room. A "hold" will be placed on the calendar, and you will receive notification once the request has been approved/declined.
Below is a chart of conference rooms that details how you can schedule each room.
When adding events to your calendar, you can add CPH conference rooms in the meeting Location field.
If your account has been given access to edit the calendar, you can open the calendar directly and add/modify/delete items. Refer to the Accessing Conference Room Calendars page.