It is working now! :)

I suppose you know it, as it happens also in the examples, but just in case it helps, I send you my console log:

https://api4.windy.com/v15.16.1/plugins/gl-particles.js --> gives error
https://api4.windy.com/v15.16.1/plugins/picker.js --> gives error
Also, "storage Failed to load lang file as .json"
I can only see the Wind selector and I don't find enough documentation to start using it. I have only found this (https://community.windy.com/topic/5078/windy-api-documentation-client-v13-00) and I suppose it is outdated for using v4.