Where put loacation directives (newbie)

I'm a newbie in Nginx and Plesk.
I'm learning to configure nginx.conf for a Wordpress + Multisite + Subdomain (with domain mapped) + https.
Now (in https) I see the main domain and its articles.
Instead, of the mapped domain I only see the home page and the articles return a 404 error.

On the Internet I'm reading various pages and tutorials and, if I understand correctly, the "location" directives must be put in a "server" block.

Plesk does not allow me to modify the main configuration files because these are generated automatically.
Intead I can place them in the domain configuration panel, but here I do not think it is possible to enter the "server" block.
In any case, there will be both of the main configuration file and the "custom" configuration file. Do not conflict with each other?

Thanks in advance for the suggestions.