How to seperate two different sites being connected

I have one site with erpnext and a custom app installed in it. The site is name demo1.local.
I wanted to create a new custom app on a different site, but I want to create it in frappe itself and not erpnext, so I created a site named appointments.local .
But the problem is that these two sites are connected so when I open appointments.local, it shows the apps which are installedd in my demo1.local.
How do I seperate the connection between these sites?
Also when I create a new site I want only frappe in it, how do I do that?

Check your nginx or dns_multitenant configuration, in your case both dns looks refereing same site

refer following document
https://docs.frappe.io/framework/user/en/bench/guides/setup-multitenancy

If you’re seeing unexpected apps or data, check sites/common_site_config.json for a "default_site" entry and remove it. Then run:

bench start
bench --site appointments.local migrate

Each Frappe site is fully independent, with its own database and apps. There’s no connection between different sites.