I am still relatively new to Squiz and have tried to set up users but not sure why they cannot load the asset they want to get to.
What comes up is a blank screen and interesting URL…
Not sure where in permissions or somewhere else I did wrong. Any help is much appreciated! 
Not sure. Edit+ configuration post 5.4 is relatively simple. I would ensure that Edit+ is installed correctly on the Edit+ Manager details screen. Ensure that the design file for the content you are trying to edit has the ‘editplus’ design area. And monitor http responses (eg in chrome devtools) when accessing _edit to see what resources if any are not accessible.
