Personal footprint library
Make a new project
Open the footprint editor (it will say no active library and you cannot save anything)
just choose a random library
Select: Save current libary as (and choose a filepatch and name for it. so you can find it again)
Go to "board view" and choose in Preferences -> Footprint library manager
add you custom library at the bottom, give it a good name and the location on your drive