Statistics is the science of getting information from data.
Statistics is not mainly computing numbers. Of course, you must compute some numbers and make some graphs. Mostly, however, you must interpret the numbers and the graphs, usually in the context of a real-world problem. Students in these classes vary quite a lot in how much attention they have paid to discussions of getting information from data. This website is a first step in providing all the students in the class with some common background as they begin the course.
Answer: You need
some skills from your previous math classes
some ideas about how to discuss data
How to think about statistics questions, Part 1
What algebra and geometry skills are needed?
How to think about statistics questions, Part 2