The capstone is the final course in your major and is taken after you have completed the rest of your major course requirements. The capstone covers the practical applications of what you have learned in your program. This is a summation of the knowledge you have gained throughout the rest of your courses. Generally, capstones consist of a portfolio project with various markers leading up to a final project.
You can find out more about your capstone in the academic catalog. In addition, you can take a look at a sample syllabus in the book list. This sample syllabus will give you a good idea about what a capstone covers. Just remember that the sample syllabus questions and assignments do differ from the actual course. To access your book list you can go here. Click on the capstone course code and this will bring up the sample syllabus.
When you are ready to register for your capstone you will need to contact your advisor. They will be able to ensure that you have met all prerequisites and can register you.