How can I link a self-designed admin panel with my self-design site?

Question

I do not understand, where should I be redirected when i log in to the admin panel..

Answer 1

You can do this in 2 ways:
1) If you are hosting your own site (or are buying a domain and server hosting through a 3rd party), then use port forwarding, i.e., if you access your web server through a certain network port (the numbers at the end of the URL you may sometimes see), then it shows you the admin panel.
2) If you are hosting it on something like Google Firebase, GitHub Pages, etc., then have admin panel stored in a sub directory of the root folder.