What basic materials can I start with?

Just finished my first year at a semi/non target and will transfer to Georgetown College next year (either Econ or political economy). I have a small internship right now but nothing business rated. I would like to try to get a great finance internship for next year and score a junior year IB internship. I know very little about modeling and questions, I have never used excel. Are the courses on WSO built for complete beginners or should I start with something else? I’ve never taken an accounting class so if I take a modeling class on here will I just be lost? I let myself have a lot of time this summer so that I can seriously develop my skills. What resources would you all recommend to me so that I may be able to prepare? If there was a popular “learning program” that would be ideal so that I can learn the basics, then how to model etc, then start learning the interview questions. Are these any posts with similar questions, I’ve done research but keep finding resources that seem built for more advanced people. Thanks guys!