This is a thing I have noticed in a lot of lemmy apps, there is no feature to go to a certain instance and view it locally. The closest is voyager for lemmy’s website, where you have to manually change the url, and then you can view the instance you want.
Amazing app so far, hope Mr.Mayayo sees this post.
It’s called adding an account on boost. Once your account is added you can easily switch between them like ok boost for reddit