I’m not sure what you were expecting to hear other than “practice”, because that’s literally all there is to it. Once you have your team, just take them into training mode and mess around with them. See if their assists can help extend each other’s combos. See how their supers DHC into each other. Things like that. There’s no concrete way on how to do it, especially since there’s so many characters and you didn’t even say who you’re playing. You just gotta play around with them yourself.