New font, duplicate master, but no way to set Axes Coordinates. Looks like the dialog is broken.
Have you added an axis in the font settings?
Ha 
No, I tried to do it exactly as it works in Glyphs 2.
I find it confusing to see “Axes Coordinates” that can not be edited, when there is no axis. Or that the Add axis is on a different page from Axes Coordinates…
We are working on improving that.
Newbie here and new to creating a font, when you create a second Master, there are various fields for Weight, I see it in Info > Masters, also in Exports Weight class which seem to be able to have different values. Also, what is Weight width?
And axes coordinates, Weight seems different.
Is there a tutorial about all this? or could someone answer (Thank you).
I see this information related to adding masters:
All I want to do is add a master, I do not want to interpolate/instances.
Is there a more suitable resource related to adding another master and setting it up so it will export along with the other master into the font options when installed.
Eventually I will want a regular, bold and outline. Currently I have bold, I will manually make each thinner for regular and then create what will be outline (probably not from the existing).
Thank you
You need to have axis coordinates in order to differentiate between masters, even if you’re not interpolating. These coordinates need to be unique for each master (so, you can have multiple masters with the same weight axis coordinate, but they need to differ on at least on other axis).
In your example, add a weight and an “Outline” axis (or whatever you like). For the outline axis, you could use binary values (0/1).
In the Exports tab, you can select “Add Instance for each Master”.