It doesn't have to be perfect- hope you can get started soon. You can also get notes from the german show Dark. I had no idea what was going in the first half of season 3 but they explained it well at the end- they basically had two different options happening at the same time and ended up using one of those to save the day. In the Star trek movie (with Chris pine) future spock and current spock could exist at the same time. Others like Harry potter say you shouldn't mix current and past you if you travel back because it would make you insane.