Hi just downloaded,
How should I pull on the gacha? beginners, or the other banners? which one?
2500 pull or 250 and reroll speedrun?
Any desired 4* unit or there is a best?
thanks
Welcome! Sorry to be the first to spam you, I'm pretty new as well, but first of all, don't panic.
Generally, the full 2500 pull is preferable, since you are guaranteed at least one 3*. Once you have enough 3*, and are gunning for new units or 4* only, there's no real downside to pulling singles either, but at the start you don't want to get unlucky and waste your stars on 2* single pulls too much.
If you want to reroll: Any 4* that has the skill "100% score boost" is recommended, besides that there's no real preference or S Tier 4* in this game that I know of.
You get 3* units from playing the event enough, and they usually are just as good as the 3* you get from the gacha in terms of stats, so don't hesitate to use them in your team as well!
If you're planning to stay F2P, it is advised that you hold on to your stars as much as possible until there's a "Dream Festival" banner with doubled rates for 4*. There is very likely one coming for the New Year in a month, if you can hold out until then. You can probably start saving stars from all the achievements you get as a beginner.
Otherwise, if you're still building teams, pull any banner you like - sometimes there will be "limited" banners, with units that you can only get from there, but that doesn't necessarily mean that those are high value when it comes to points or skills, but some people love collecting those most.
Once you are starting to have teams of specific colour, you might want to hold out for specific element banners to fill out your teams: i.e. if you're missing "Happy" team members, wait for an event with the Happy element, at the end of the event there will usually be a banner with higher rates for Happy 3* and 4* members.