Hey there.
You can see an example of basic authentication using Powershell here:
And, your version is past EOL. You should upgrade to either the latest version or the current LTS at your earliest convenience. Your upgrade path is:
9.3 → 9.9.3 → 10.3 (last step optional)
You may find these resources helpful:
If you have questions about upgrading, feel free to open a new thread for that here.