games and more => solo is all the main modes. So try them, classic is your basic fighting game tournament where you can complete it with everyone. But there's also allstar that's a similar mode.
Then there's events which is something to work through one by one.
There are so many modes hidden away it's awesome!
THEN there's master orders that are quick one off matches that get you stuff.
But also you unlock stuff no matter what you do really.
There's some 2 player co op stuff in games and more => group (classic, allstar and events)
Coins are got anywhere and are used for a number of things, but main one to be bothered about is buying trophies in games and more => (far left option) => trophies, then go shop or trophy rush.