You can attend either a standalone program or one associated with a university. See if there's a program nearby that you can attend by checking the list at https://www.brewersassociation.org/resources/schools-organizations/. This list has most of the schools in the U.S. and a few international schools, as well. How you apply depends on the school or university. For instance, at a university, you'll likely need to apply through the school's admission office. In that case, you'll need things like your transcripts from high school or other colleges, references, and a personal statement, as well as a completed application form.  Non-university programs will have a similar application process. You may be required to prove you've taken certain prerequisites, as well as describe the brewing experience you've had. You'll be required to fill out an application form, and you'll likely need to pay a fee.  Some programs have scholarships you can apply for. The amount of coursework you'll need to complete varies widely by program. You might do a certificate program in a couple of semesters. Other programs might be as long as 4 years, or possibly longer if you continue on to graduate work.  In some cases, you may need to pass an exam at the end, though it depends on the program. In most programs, you'll be doing hands-on brewing in conjunction with what you're learning in the classroom.

Summary:
Find a brewing program. Apply for the brewing program of your choice. Complete your required coursework.