Make Win + - print medium dash?

how does one do this “simply”?

in settings > input devices > keyboard > layouts > configure > Add

i only seem to be able to choose between a l-o-n-g list of preset keyboard layouts… there is one option that says “A user-defined custom layout” all the way at the bottom of the list, but it gives me this error when i try to preview it

not sure where to go from there….

EDIT:

figured out how to create my own keyboard layout to add the emdash

here is a preview of the entire mapping