Dragonball Xenoverse 2 does not give you detailed information about the combination mechanics. It only drops pieces of information during the game. Playing with a game that requires good execution of combination moves like Xenoverse is pretty hard especially for beginners. If you're a rookie, this guide was made to help you figuring out basic tricks in doing combos.
Simply Spam Punch And Kick. The combo list in the options menu does not really matter that much because in the end, once you press the square or punch multiple times, it will allow you to perform an auto launcher. The auto launcher is supposed to be followed by a special move of your choice. Another trick is pressing the X or the jump button after multiple punches. This gives you an advantage to spam attacks all over again and then execute your special techniques. You can end your attacks with an ultimate to deal a solid amount of damage.
Watch Your Stamina. Pressing square and triangle multiple times is the basic combo one can perform. However, you may not want to spam punches and kicks until you lose all your stamina. This will lead into bad situations especially when your opponent gains momentum. The most profound thing to do is have a stamina break every once in a while until you are ready to go again.
Launch Your Opponent In The Air. When you're in a risky situation, like having an immediate need of stamina or an escape, you can launch them away from you. The combination for this is triangle plus circle. You can also throw them away with only pressing the circle which is a basic move, however, you need to be close enough to do it. Another way to take advantage of this combo is making follow up moves after throwing them away.
Practice Performing Combinations With A Quest. If you want to know more about combos, you can go to Elder Kai and try out Quest Number 13. The quest gives you ideas about combinations in the game. You can also train yourself and explore creative combinations that suit your playstyle.
To sum it all up, there is no specific combination since there are different abilities and different characters present in the game. You only need to be creative in performing random smashing, kicking, launching and throwing. You also need to manage your stamina to make sure you can perform your special skills and ultimate ability to end your opponent.
