The analytical reasoning (AR) section is commonly called the games section. A better name might be puzzles. Basically, the AR section is composed of four separate puzzle-like set-ups. In each set-up, there are variables that shift around or are constrained in some way or another, and you must find answers to specific inquiries that can be made given the set-up (either generally, in some way further constrained, or revised).
While there is some overlap in the skills involved in master of the AR and LR sections, it makes sense to address the separately, as the AR section involves a very important skill: the capacity to convert the initial verbal description of the puzzle that the LSAT provides into a functional diagram or picture that is then used to answer the questions. Mastery of the AR section involves drawing, drawing and more drawing. By drawing here, we mean something specific and structured, and it is important for the student to appreciate exactly why such drawing must be used and how it works to lead to achievement on the AR section.
Most prep courses understand that the AR section involves diagraming, but think that a collection of stock diagrams will be enough for the student to master AR. However, mastering the AR section is not about having in mind a ready-made diagram for every type of puzzle that the LSAT may throw at you. This is because there is no end to the different types of puzzles: this is why most prep courses have a catch-all category for the puzzles that do not fit their other efforts at categorizing the puzzles. Not to say that there are not some crude categories that can be observed across previous AR sections. But memorizing such categories and examples is no substitute for an understanding of how to generate a functional diagram from scratch and being ready to handle the analytic process tested on the AR section generally, no matter what the LSAT happens to invent in the way of AR puzzles.