Thanks for that, got to the third stage but I got killed, I still dont Get the battle system or the battle order so I must play the game more I guess
You'll get the hang of it, don't worry. Some important stuff regarding battle order (I didn't know how it worked either until someone pointed it out to me):
Characters on your first two left slots come back in two turns, and the one on the third slot (right side) comes back in three.
So, as an example, let's say you start your match and on the FIRST turn you have Super Vegito attack first, Gohan second, then Whis third.
On the SECOND turn you'll have 3 other characters, place them as you need them. And on the THIRD turn, your Super Vegito and Gohan come back, plus the seventh character that still hadn't appeared.
On the FOURTH turn, you'll get your 2 left characters from the SECOND turn, plus that Whis from the FIRST turn. And so on. The basic strategy is getting your characters in your preferred positions and never letting them leave those slots. However...
It's important to know that sometimes you can't keep your characters in your desired positions because they might be needed on others. For example, maybe you have an enemy attack 3 times on the last slot and the only guy you can use it to block and survive is Super Vegito. Then you'd have to put him there and just try to deal with having him out a bit longer. In general, you should try to keep characters that link well together (mainly links that give more ki or more attack, or a certain link that's needed to damage an enemy, like the Fierce Battle mentioned above).
This is where items are useful. The "main" loadout is two full HP recovering items (Senzu Bean and Dende) plus 2 support items (the most popular / useful are King Yemma to reduce incoming damage by 50% on that turn, Ghost Usher which makes all enemy characters not attack on that turn, Baba to turn enemy Supers to normal attacks that turn, and Oolong + Puar to change orb colors. There are others who do the same / similar things, and other who give more Ki, etc).
There's a very important trick you can use: if you see an enemy doing a Super attack and you know you won't survive, just close the App immediately (before the damage numbers finish rising and "KO" appears), and when you restar you'll get a message saying "continue suspended game?" and you say yes, which brings you back to the beginning of that turn, so you can use an item or change positioning to try and survive.
The other basic rule is Type advantage, you can see the advantage circle on the upper right of the battle screen. If you use an AGL (blue colour) character against a STR one (red colour), you will do more damage and you will receive less damage when he attacks you.
Give it a try on low stamina stages so you can get safely used to it, instead of trying to learn during the hardest stages, which can be overwhelming.