I shared my very basic and easy setup with Caddy + Authelia some days ago.
If you are deadset on using NPM tho, i find that is harder to share a exact config because its UI based.
In general its a good idea to provide details of how exactly something has failed for you, instead of saying "it has not worked".
Chances are high that someone spends their time and shares and explains their NPM+Authelia config to you, and you run into the exact same problems again and "its not working".