Filling out the AADSAS application is a lot like filling out a detailed job application. It starts with basic information like your name, address, phone number and Social Security number. There's a section on your family (in case any of your immediate relatives went to one of the schools you're applying to, which can factor into admissions decisions), and a part where you can describe your background, including whether or not you qualify for disadvantaged status.
From there, you fill out information on your education, starting with high school, and then moving on to your undergraduate years. There's a system for having transcripts sent to AADSAS and attached to your application. You'll need to note your coursework and DAT scores, if you've already taken the test when you first create your AADSAS account.
One of the more important parts of the application is labeled "Professional Experience." Here's where your volunteer work or shadowing time in the dental or other medical field will pay off. Of equal importance is your personal statement, which allows you to explain why you want to be a dentist. (Make it more interesting than, "I just want to help people" to set yourself apart.)
At this point, the application is almost finished. You need to read and acknowledge some formalities indicating that you want AADSAS to release your information to dental schools. Pick which schools you want to apply to, and the application is done. Some portions of it can be changed later (for example, if you retake your DAT or if you apply to additional schools).
Most dental schools have rolling admissions, but the schools agree not to mail out acceptance letters until December the year before entrance, which is roughly six months after applications are first accepted. Applying late in the cycle can make it harder to get into the school of your choice, because there will be fewer spots still open.
The amount of time you have to respond to acceptance from a school and send in a deposit to reserve your place in the class varies from school to school, but it's typically between one and two weeks.
Head to the next page for more information on dental school admissions.