These are the steps to add parts to the library, up to KiCad v5.1.10.
Note: Make sure that KiCad is connected in your Tools tab.
Open SnapEDA Desktop App
Search and click the part that you want to download
Then click Add to Library on KiCad
Note: This might take a few seconds but please don't click the button multiple times. Wait until the notification appears
After a few seconds, KiCad Pcbnew will automatically open
Note: The reason why we are opening the Pcbnew footprint layout instead of the schematic is that KiCad doesn't yet support APIs with the schematic layout.
Add footprints on KiCad and see that the part is now under SnapEDA Library
If you want to open or place the symbol on the Eeschema, simply search the part downloaded on the Choose Symbol window or Symbol Editor window.
Note: You might have to restart KiCad for the symbol to appear on Eescheema. This is because KiCad doesn't yet support APIs with the schematic layout.
8. Unfortunately, the 3D models are not integrated with the footprint (this is already being developed).
However, the 3D models are still downloaded (if available). You will find them in the following path:
C:\Users\<Your Username>\SnapEDA Kicad Plugin\KiCad Library\SnapEDA 3D Models
If you need to import the 3D models, please follow the steps described in this article: How to import a 3D model in KiCad?