Rough plan
1. Chevalley group schemes: explicit functorial viewpoint through Chevalley basis of semisimple Lie algebra
2. Generalities on algebraic groups/group schemes
3. Limits/dynamic descriptions of subgroups
4*. One or two selected topics. The current one in my mind is Richardson's proof of the Matsushima criterion.
Main references: Steinberg's Yale notes, Milne's book, Conrad's various notes