In order to connect to a WEPN gateway via Outline app, you must be first invited by a WEPN server owner (provider).
The provider can be a friend or family who has set up a WEPN device at home and invited you via email to gain access to their home server.
Optionally you can set up your own WEPN device and become your own provider. This was you can route your traffic through your home network at any time.
However, if you are behind a firewall or reside in a country that regulated and censor online content, then setting up a WEPN device at home is not going to let you pass through the firewall and access to the blocked content.