Start with Fusion 360 Tutorial for Absolute Beginners (2020) (35 min, Product Design Online), then Fusion 360 Snap Fit Cases (35 min, Product Design Online). All 174 lessons here are free, from the teachers' own official uploads. You'll need laptop stand, noise-cancelling headphones, second monitor and a few more basics (about $270 of kit). The book to keep beside you: Fusion 360 for Makers by Lydia Sloan Cline.