Can someone enlighten me as to the order in which you should be doing campaigns/Legend Stages?

I am at Into the Future 2, I can start Cats of the Cosmos (tho I believe that might be unwise), I also have Legend Stages (I didn't do much of the normal ones, only the first stage batch), I also have a lot of event stages, some of which I can do no problem, and others destroy me completely. I know there is a star meter, but I don't quite know how it works, there are some pink stars, others are normal yellow, some campaigns/stages have multiple stars, others only one.

Ideally, if someone could provide me a list of the order in which I should do stages/campaigns/events, I'd be grateful.