Green dot means connection can be established.
you rarely need the domain field.
Share name should be the name of the share without any extra characters. You can check the share name on your server. There is probably something like \AD\Share1. You only need the share1 part because the app, external storage, puts host+share name and looks this up.
Subfolder is only needed if you have a parent share which is accessible by everyone, and a subfolder that you want only the user to have access to.
I would keep it simple, fill out the host, share, user and password fields and try to access it.