Just call in the webapp-backend folder:
go get ./...
go build
then you can copy the executable anywhere you like and run it from there. All static files are embedded into that executable.
In the webapp-frontend folder follow these steps:
npm i # Restore all npm package
npm start # Run the development server
# Now make any changes in the webapp frontend you like (ex. add static files, change components, css or js files etc...)
# Next build the production files
npm run build
Now change into the webapp-backend folder and execute the following commands:
go generate
go get ./... # Only if not already done before
go build
Again copy the executable anywhere you like and then run it from there.