This video shows you the process of adding a shaepfile that you have created elsewhere (ArcGIS, etc.), downloading it to your system, and then uploading it to GEE. Once you upload it into GEE it is an asset you can call like any other feature collection using Python Code.
To access this part of GEE you must log in to the code editor:
https://code.earthengine.google.com/
Once logged in you follow the video instructions by clicking on the assets tab and uploading your asset. The easiest way is to upload your entire set of files representing your shapefile as a zipped folder. Once this is uploaded the GEE it will take a few minutes for it to show up in your pane. Here is the GEE support page about this process. Once your assets update you can click on any uploaded asset to get the specific path name you need to reference in the GEE python code (Table ID here):
You can see how to then use this ID as you would any other feature collection in the following python code:
https://colab.research.google.com/drive/1szcHbrYho1AuK7SSsPNGHDs8uAQdwRFO?usp=sharing