I'm trying to set it up for use with OpenVPN. For example use this guide :
When i try to add new connection and set it up, on the tab "Switch to advanced configuration " > Service | Networking | VPN | Cryptography
all tabs are empty .... I can not edit or add setting
screenshot: https://imgur.com/a/RiwbFnS
and so in all the tabs - Service | Networking | VPN | Cryptography
where is my error?
OpenVPN should be configured via SSH, not LuCI, as the LuCI OpenVPN app is beyond convoluted (I recommend having it installed only for the ability to quickly glance at the OpenVPN page to verify the VPN is up and running without issue).
luci-app-openvpn needs to be re-tooled or rebuilt from the ground up because of how convoluted it is, which is unlikely to happen. Majority of the options in the LuCI app need to be removed and replaced with a simple code box to enter custom parameters.
OpenVPN is one of the services that is far easier to setup via cli than via LuCI's GUI app, and a user will need to login via SSH anyways to check the OpenVPN log file after setup to ensure there's no errors
I personally recommned a client log verbosity of 7, as that verbosity level outputs everything needed to troubleshoot an issue.