Configure Network manually

I woulr like to configure manually but it seems impossible with the applet or with sudo; How to do ?

I reply to myself :
I install and launch as root nm-connection-editor (gnome) and it seems to work.
Before closing as SOLVED any suggestions are welcome.
I tried without being root and it works fine.
I can’t modify with kde networkmanager applet in the systray.

The networkmanager applet should just work fine. Not sure what your problem is there.
I can configure a manual ip address without a problem there.

i do not know what happen but the ‘apply’ button stay on grey and no change is made if i click OK.
Maybe a mistake in my ipv6 address or something like that.
No matter about it i go back to pure Debian (Sid) even if i think ‘netrunner debian’ is among the best distrosp
Thanks for your reply.