Once you’ve decided when to take the test, navigate to https://www.lsac.org/, create an account if you don’t already have one, and follow the instructions. Registration closes roughly one month before the test date. It behooves you to plan ahead and register early. Your mentor can help if you need guidance.
Throughout the pandemic, the LSAT is offering what it called the LSAT-Flex, an at-home version of the test administered digitally. Rest assured that if law school is in your plans, the pandemic won't ruin them.