S3 Connector

Hello,

I am trying to use the S3 Connector but encountering some issues. I was hoping someone could help illuminate what certain fields are for. For context, I am using Auth0 to have users log into my site. Users should then be able to upload files and send them to an S3 bucket.
I followed the instructions here, but could someone elaborate on the different fields in the Sign Upload URL and Set Value steps?

S3 Steps