The LSAT is a digital standardized test required for law school admission and is comprised of five 35-minute sections: two Logical Reasoning sections, one Analytical Reasoning section (also referred to as "Logic Games"), one Reading Comprehension section, and one experimental section that will not be scored. Unfortunately, you won't know which section is the experimental one, as it will be in the same format as a scored section.
You will also need to take the 35-minute LSAT Writing separately. It is included in the LSAT fee and available on demand up to 1 year after your test day; you can also purchase it by itself for $15. LSAT Writing must be completed before your LSAT score will be released to law schools, but only one needs to be on file for your score to be released. So if you decide to re-take the LSAT, you do not need to complete another LSAT Writing, although you can if you'd like. While LSAT Writing is not scored, law schools will be able to see it.
One way to prepare for the LSAT is simply to take a lot of practice exams. LSAC, the company that administers the LSAT, has also partnered with Khan Academy to offer free LSAT prep. If you decide to enroll in another prep course, look for one that uses real LSAT questions. You can also get standalone prep books, like PowerScore's Logic Games Bible.
Plan on taking the LSAT once, but leave time to take it twice. Scores generally only improve by a few points on subsequent tests. However, life happens, and if something unexpected happens that prevents you from performing well on the LSAT the first time, you'll want to have that cushion.