Figuring out how to forge friendships between two characters

Hey guys!

I’ve been struggling a bit with finding a good way to form a bond between two of my characters who don’t initially click.

For context, it’s a historical fiction set in the late 1800s. The story kicks off when my MC, Libbie Hopkins, moves from central Pennsylvania (her family has roots there from the American Revolution, which is in connection with a different story I started) to a frontier town in Nebraska. Her family is traveling with another family, the Cullivers, and this is when she is first introduced to Etta, who is close to her in age. As of right now, the beginning of my story is a little weak, because I have a lot more fleshed out after they’re living in Nebraska. Once they’re in Nebraska, the girls are best friends, but I haven’t figured out how to get them from point A to point B. When they first meet, Etta is really quiet and shy and keeps to herself most of the time, so Libbie finds it hard to connect with her. I need a good link, something that happens, that brings them together, probably while they’re traveling to Nebraska, to show how they formed a strong bond. (Their friendship is just one arc in the whole story, but it’s the one thing I’ve been struggling to piece together lately)

So if anyone has any good ideas of something to bring them together, especially something that would be relevant to that time period, please drop your ideas in here!