Get "No HTML file named CredentialsUi was found." error

Check that it was created as an Html file and that the case matches exactly

Spreadsheet menu doesn't appear

From the Script Editor

• Open the Initialize.gs file
• Run the onOpen function

Get "SyntaxError: Unexpected token: <"

From the SAP Gateway Menu set SAP Credentials

If all else fails

Take a look at the finished code