All CollegeBoard exams (PSAT, SAT and AP tests) are accessed through the College Board website.
To register for an exam, your student must create an account at
https://www.collegeboard.org/, select the desired exam, and follow the registration prompts.
This process will lead you to location listings.
To register for the PSAT, do not put in your school name, just your state and zip code. This will generate a list of schools that are administering the exam in your area. From there you will need to contact the individual school and request for your homeschooled student to join them.
When taking any CollegeBoard exam, the student should include the HCS school code #052839.