I don't know what it's trying to say.
Rooms are available 6 days a week? Which day is not available?
Or: People can make reservations 6 days a week? Like, "Don't bother to call on Fridays, but you can make reservations on any other day for a stay on any day"?
The person who takes the reservation is supposed to enter it in the calendar?
Rooms are usually booked two to three months in advance. This part would mean that if you don't have your reservation in 8 weeks before you want the room, you probably won't get it.