I am studying the Rime of the Ancient Mariner at AS level and find some aspects confusing. It would be hugely helpful if anyone could answer some questions on it or had information on it.

Firstly, when the poem begins it is in 3rd person but switches to 1st in the second stanza then returns to 3rd person. I do not understand the significance of this?

I'm also confused about the idea of the encounters taking place on a threshold?

If anyone could help that would be great! Thank you.