I mean, it said it right in the walkthrough - buy vegetables at the shop. It doesn't get any clearer than that. Alternatively, you can grow vegetables with Penny, but that will take awhile for vegetables to appear, since they take time to grow.
As for hunting, you just find a rabbit and walk up to it. Then the hunting screen pops up and it will randomly determine if you shot the rabbit. If you successfully snuck up on the rabbit, then you have a better chance at succeeding on the shot. If it saw you and starts to run away, then it will be unlikely that you kill it.
If you don't know where rabbits are, just go back to the place you went to with Marcus to hunt during the introduction of the game. Go up the ladder of the little tower and enter the sparkle to start hunting. Randomly, either a rabbit, a deer, a wolf, or an orc raiding party will show up. If orcs, you should probably run south or west to exit the screen to escape the orcs, until you are ready to fight orcs. If a wolf, do the same. Only go after deer and rabbits, at the beginning of the game. Rabbits are the easiest to hunt.
