Simple URL problem for new articles & posts

Greetings,

I have a site:

https://example.org

and a blog:

https://example.org/blog

Problem: when I create a new page / article the url will be https://example.org/new-article and NOT the preferred version: https://example.org/blog/new-article

Solutions: I have tried to solve the problem by moving WP from root to a subdirectory (by using FTP), but the URL of a new page / article still remained in the not prederred version: https://example.org/new-article

Is there a simple solution to this, am I making it too complicated?

Best Regards,
TOVK