All is finished, but I do not see the server on the list. What to do ?
You dont see it because you forgot to install a requirement.
And do you know which one ? 
Yes what is that please ?
Have you read the guide to setting up the server on Linux?
We watched this video : [How-to] Setup a GTA FiveReborn server on LINUX
We followed it step-by-step.
Is this coming from echo? Because we have not installed it, and we can not. We are root
echo “deb http://download.mono-project.com/repo/debian wheezy main” | sudo tee /etc/apt/sources.list.d/mono-xamarin.list