Could somebody please explain this game to me?

I decided to pick this game up after finding out that it has an English fan-translation. I just started and I have no idea what's going on. The first two levels of this game just seemed like complete clusterf**ks of random things happening for no reason. I also have a bunch of characters I have never heard of before. Is this a sequel to another game or something? Did a accidentally skip a bunch of cutscenes somewhere, somehow? I've only played two levels and I am completely lost on this game's story. First level had a bunch of different Gundam main characters fighting ELS together until some of them got mind-controlled by someone or something and they starting fighting each other. The second level seems completely disconnected from the first one, featuring the very first battle of the original Gundam anime (which is odd because Amuro was his CCA self in the first level), and then my characters (who are the aforementioned people I've never heard of before, along with the "master" I was prompted to select upon finishing the first level) show up to join the fight without any explanation, and without Amuro or the Zeon soldiers acknowledging their presence. Then a bunch of other heroes and villains from other Gundam shows gradually appear to join the battle, then all of the characters on my side except for the people I've never heard of and my "master" get mind controlled again and I have to fight them, and....that's it. That's the end of the level, and there wasn't so much as one single cutscene explaining what's going on. I am so very confused.

Could somebody please shed some light on this matter for me, please?

In addition, I'd like if somebody could explain some of the gameplay stuff to me. I have no idea what a "master" is, and I just picked a character that I liked. I poked around the main menu between levels, but I don't know what anything is or does, so I just left it alone. I've never played an SD Gundam game before, so I really have no idea what I'm in for.

Thanks!

- first stage is just a prologue
- after prologue you are proceeding to the main game include three routes : world tour - world core - overworld
- in the main game you are free to build your own team.
- master is master unit, a mothership / warship can have up to 1 master 2 group leaders, master unit increase other unit stats if they are staying within the master area (hover the cursor to master unit you will see a purple color zone). Master unit can initial support attack with all other units within master area.
- group leader is almost the same as master but they can only initial support attack with members in their group only, members in the same group can initial attack with other members and group leader too if they are within the leader area.

Thanks. Could you explain all the menus to me as well, please?

And could you explain the story to me too? I have no idea what's going on, or who any of the characters I started with after the prologue are (besides the master I picked). I started with Banagher and Setsuna fighting ELS, then Amuro, Kira, Domon, and Flit showed up to help, and then those four got brainwashed or something and turned on Banagher and Setsuna, then they seemed to be back to normal after Banagher and Setsuna beat them, and then the level ends. The next level, rather than being a continuation of that "prologue" level, seems to be something completely different. It's the first episode of the first Gundam anime, with a whole bunch of random people from other shows showing up one after another, and then everyone who was on my side except for my master and the characters I don't know get brainwashed like before, then I beat them and that's it. I'm very confused. I haven't played since I made this thread, having been preoccupied with other things.

G Gen Overworld is a sandbox game where you visit a bunch of gundam world randomly. Don't think too hard about it.

Basically, there was a system that went bonkers. The system, created a rift where certain non canln series emerges in a scenario ie Age, 00, ZZ and Seed in UC0079 Gundam Rising. Generation Break is what its called, Over Impact kn the other hand is when the so called systen in universe can't handle the strain GB causes. This turns Guest characters to fight turn against you and amplify or create flaws of said character. IE Flit being egotistic and acting like he's the best etc. Heero seeing you as the enemy or Setsuna making you a target for Armed Intervention.