Arrange is to organize. I like to arrange my desk before I start working. Can we arrange a session for Friday? Adjust is to modify or change a little bit. I need to adjust my seat it's too high. Can we adjust our session time to 30 minutes later?

Adjust is like if something is in disarray, and arrange is putting something together (from the start.) Ex: I adjusted the flowers after Justin knocked them over. Ex: I arranged the bouquet from flowers I found in the garden. OR: I arranged a meeting with Steven. Hope this helps!