i need to get organized!

hi so i'm about to go into my senior year of high school and i've got lots and lots of things lined up to keep track of. anybody know of any really nice, user-friendly apps for a lenovo laptop with a microsoft program? i need something that can help me make different types of files from calendars to to-do lists to other planning/note taking files. i'm not very techie so i need something navigable and organized. thanks!!