You want to map frontend/web and backend/web to separate domains. And it really depends on your webserver where you would exactly do it. As for Apache, it would be some .conf file, most likely httpd-vhosts.conf. Google something like "setup virtual hosts yourwebservername" for more details.
Since the template supports relative paths and can exist in subfolders, you don’t really need to set it up as separate domains for study purposes.