>>53337824>>53338157NTA, but I just started last month so I'll give you some pointers based on my own experiences on what you need to know and what you have to do:
>Do the story modeDo this first. There's some characters here you can get for free that are actually pretty useful. Like what
>>53338087 says so. (Chapter 8 being Skyla. Once you get her, you can pretty much ignore the rest of the chapters unless you want to play the story.)
>Which other characters should i get then?Once you get a good enough team, you can tackle on Legendary Adventures. They happen after the main story, but that doesn't matter. It's recommended to do Professor Sycamore's story because you will get him and Xerneas, and they're the best Free-2-Play unit that could carry you throughout most of the game.
>What's this re-roll thing people keep talking about?Gacha games are about rolling for the character you want. It's the Japanese version of lootboxes.
When it comes to what the other anons are saying about re-rolls, check out the second link in the OP. You can roll for whatever character banner is currently available on the shop once you reach Chapter 2. (The game will reward you 300 Gems by that point, which is enough for 1 roll)
If you don't like what you got, you can wipe the user data from the game menu itself and reach chapter 2 again to do a re-roll. I personally wouldn't recommend this because of how tedious it is, when it's generally better to do the bundled 11x roll on the banner you want. (3000 Gems for 11 rolls)
Getting 3000 gems would take awhile, but they're currently giving away 3000 gems for all players. This is the perfect time to do re-rolls.
I'll continue on next post since I reached the limit... 