The LSAT is scored on a range from 120-180. The test consists of four scored sections (2 Logical Reasoning sections, 1 Logic Games section, and 1 Reading Comprehension section) and one experimental section - which is one of the above 3 types but doesn't count toward your final score - along with a short essay. You write the essay at the end of the test, and starting later this year, students will complete the essay as a take-home assignment instead.
Your score on the 120-180 scale is determined by how many questions you answer correctly. There is also no penalty for wrong answers, so you should at least guess on every question.