Right click the Solution in the Solution Explorer and select Open Folder in Explorer.
The following simply shows where the project folder is, but this is not the one that gets zipped…
Go up one level or twice to find the solution directory…
The following is one folder up and that is not the folder to zip…

Move up one more time. This is the root folder that needs to be zipped.

In order to zip it. Right click the folder and select ‘send to’ then select ‘compressed (zipped) folder’