Head back across to Bonnie’s house and you’ll start the next mission in her strand. This is a very simple introduction to using a horse and cart and the only real difference is that if you hold the slowdown button (RB/R1), you’ll start to reverse slowly.
Jump onto the driver’s side of the carriage and drive Miss Macfarlane to Armadillo. As long as you don’t try to rush it and stick to the yellow route on the map, you’ll reach your destination after a chat with Bonnie.
Once you get off the carriage, head across to the doctors (indicated by a yellow X). When you get inside, buy the potion off the doc for free (after this you’ll have to pay for any more). Now go back outside and speak with Bonnie, where she’ll leave you to explore the town of Armadillo!