When your time ends, stop that section and move on to the next one. So choose one of those methods, sit down without distractions, get a timer, and do the full LSAT based on the test conditions (35 minutes per section, a short break in the middle). If you'd prefer hard copies of the test, LSAC sells book versions too. So each has their pros and of course you can use both. 7sage, from what I've heard, does a really good breakdown of what kinds of questions you're struggling with and how to improve, and you can practice on just those questions. Lawhub is great because they let you use the actual software/interface of the LSAT, so you can get more used to it. My suggestion, either sign up for their Lawhub service or for a third-party service like 7sage that will let you take full practice exams.

LSAC used to have a free full sample test on their website, but I think it's from 2005 and the test has changed somewhat in the difficulty/wording of questions.

Take a diagnostic exam under test conditions.

Lsat khan