What the hell am I supposed to do?

I have never played any of the HM games, and this one sort of just throws you into the game. I skimmed through the manual, and I planted some cucumbers, now what?

Yup.

But seriously. Just plant stuff. Harvest it. Use it to buy more stuff. And talk to the villagers. Use that to buy animals and feed. Etc. Build a good farm that you can be proud of and just chat with people. Its a pretty chill game and sometimes you'll get a heads up of something you ought to do like participate in a festival but you just need to make sure you focus on making your ranch clean and full of crops and animals.

Back to Nature is pretty lax compared to the games that came before it. Just...do whatever you want. I mean really, the game clock moves slowly and you have three years to meet requirements most people meet by the first spring.

Harvest those sweet cucumbers then plant some more! Then do farming with cows. The possibilities are endless.