I suggest you look into a tutorial for creating footprints. One example could be the one I made Tutorial: How to make a footprint in KiCad 5.1.x? but there are others out there including some on youtube if you prefer videos.
And regarding your scaling issue: is it possible you set kicad to metric and entered in Imperial or vise versa? (Kicad out of the box is metric. The file format is metric. So I suspect there are less issues for metric users in general but I can not judge this as I never work in Imperial)