Here is the process I use when setting up Multi-Tenant DNS on frappe bench
`
bench config dns_multitenant on
bench new-site library.dev
bench setup nginx
sudo service nginx reload
bench --site library.dev install-app library-management
Repeat steps 2 - 5 for every other site you wish to create
To access the sites you will then use http://library.dev:8000, http://library1.dev:8000 and so forth
Reboot bench server
bench restart