While KM does have tokens that make accessing and pasting the front Safari URL easy, there's nothing KM specific about this step. You can copy it like you would any other URL (i.e. click in the address bar or hit ⌘L, make sure the whole URL is selected, and copy like normal, probably with ⌘C.
The whole point of this is to work around 1P8 not working with the 1Password Bookmark action by effectively making a replacement for it.
This lines up with my experience too; some websites seem to need a manual click in the login fields before the credentials are filled. Not ideal, but at least it still works as-is for some sites, which is better than nothing.
You don't. You only need to copy it to a KM Open URL action so that you can use it in a macro in the future, as an alternative to the currently non-functional Open 1Password Bookmark action. Yes, once 1P8 is updated this should all be unnecessary, but if you want to use KM to open websites and fill in credentials with 1P now, this is the simplest way to do it, as once the Open URL action is set up, it's just a single action akin to Open 1Password Bookmark. In other words, this for 1P7:
I understand that it is a workaround for 1Passowrd 8. I did not -- at least until now -- understand that the Copy portion of the Open & Fill URL was to be done manually and entered / used in the KM Open URL action.
Now that I understand, I have built the macro that you had in mind and it works inconsistently for the Josh website (because I generally, but not always, need to press tab to move into the credential fields) and consistently for other (where I do not need to ever press tab to move into the credential field).
Please see the macro below, is this what you had in mind?
Worth noting, I need to add an if statement at the start of the macro to make sure that 1Password and, if not, then open 1Password as this will NOT work without 1Password being open!