I had the same question, so I emailed them. This was the response:

Thank you for writing. Our records indicate you are registered for the January 2021 LSAT-Flex test.

Scheduling at go.proctoru.com will open approximately 10 calendar days prior to the first test date and you will receive an email from LSAC when sign-ups are available. The testing dates are January 16th and 17st for most test takers. Please do not attempt to choose a testing time slot until scheduling has opened.

Before you have a Proctor U account, you may test your equipment at test-it-out.proctoru.com.

Please create an LSAT Prep or Prep Plus account (Law Hub) if you have not already done so.