How do I pass the password in using scipting?

I have set up a script to log on to a SFTP site.
The script does connect, but asks for a password.
I see no documentation on how to provide the password via a script

You specify your password in session URL in your open command.

open sftp://username:password@example.com

See
https://winscp.net/eng/docs/scriptcommand_open
https://winscp.net/eng/docs/session_url