Log onto the Internet and direct the browser to your airline frequent flyer's website. Look at the back of your club card to find the website, or use the airlines general website and follow the frequent flyer miles link. For example, Delta Airlines has a link for "Skymiles Benefits" off of its homepage.
Follow the links to the air miles benefits and click on "Lodging", "Hotel" or other terms indicating accommodation based benefits.
Enter in your destination city and select a lodging option from the menu. Enter in your travel club membership number. If asked for traveler numbers, bed choice and amenity options, fill them out according to your travel needs. Click "Enter" and wait for the confirmation and reservation number to appear on the screen.
Print out the documents for travel and check-in. Be prepared to present a valid credit or debit card upon check in at the hotel for incidentals. The miles are used for payment but most hotels require valid credit or debit cards for security and additional amenity fees.