Start with 7 Amazing Exercises No One Does (ALL S TIER) (16 min, Jeff Nippard), then 7 Things That Helped My Shoulders Grow (14 min, Jeff Nippard). All 1170 lessons here are free, from the teachers' own official uploads. You'll need adjustable dumbbells, weightlifting belt, pull-up bar and a few more basics (about $420 of kit). The book to keep beside you: Starting Strength by Mark Rippetoe.