Hotel database assistance

Hi, you've got a classic "Many-To-Many" setup here ... one Customer can make many bookings, one Room can have many Customers. Access (and other databases) need a joining table to make sense of it. You've got a Primary Key for each table so far, right? CustomerID, RoomID.
You need to make a third table, Room Bookings, with the following fields (at least) ---
CustomerID (Number, Long Integer -- check the bottom half of the screen in Design view)
RoomID (Number, Long Integer)
Booking Date (Date).
To prevent double-booking a room, you need a compound Primary Key. Do this:
In Design view, click the RoomID field in the left border and Control-Click the Booking Date field. Both should be highlighted. Then click the Primary Key icon on the toolbar -- you'll see key icons appear next to both fields. Save the table, and you should be ready to go.

This is the table in which you make all your bookings. You should create a Booking form based on it. The table should be related to the Customers and Rooms tables, One-to-Many, with referential integrity applied.
If none of this makes sense I'd recommend that you attend a 2-day Access Introduction course, and and 2-day Access Advanced course. Generally the Intro courses show you how to USE a database. The Advanced courses show you how to DESIGN (or at least get started). You can also get a good primer on the table design process by going to this link
http://support.microsoft.com/search...dType=ANY&maxResults=25&Titles=false&numDays=
and downloading the relevant file for the version of Access that you use. It's based on the Northwind sample database that ships with Office.

HTH
Denis