What do you do on it also which version do you recommend
Playing on 3ds and I recommend it.
As to what you do its kind of hard to explain you might want to look up a video. Basically you're mainly battling fishing catching bugs and collect materials. You can work on expanding your towns facilities and upgrading your items. It's setup somewhat like Monster Hunter if you've played that.
Underrated youtube channel https://www.youtube.com/channel/UCjfV8aKrUfC0wwtCypieUUA