There are few different ways to apply to college. By far, the most common way to apply is through the Common App, which is accepted by more than 1000 colleges and universities. Some schools don't accept the Common App, but may instead use the Coalition App or their own school-specific application. Here's a simple explanation of all the options.
Since most students who apply to four-year schools will need to use the Common App, that's a good place to start getting a feel for the process. Set up an account, add schools to your list, and get started.
For self-guided application support, the Common App itself offers a helpful guide. Another great resource is The College Essay Guy's College Application Hub.
Four Rivers students can get support with the Common App in Junior and Senior Seminars and one-on-one with college and career coach Leah Plath.