I now want to install an app launch in my start menu. I did this by
cd ~/Electrum-3.3.5
sudo desktop-file-install electrum.desktop
This installed the app launcher in my menu://applications/Internet directory (although it was a hidden app so I had to unhide it).
For this app launcher the target file is "/home/richard/.local/share/applications/electrum.desktop" and the command is "electrum %u"
The only problem is that when I try to launch Electrum in my start menu nothing happens. Where have I gone wrong?
Since you need
sudo/
su to run Electrum, then probably command in electrum.desktop doesn't include
sudo at the beginning of the command.
You might want try running the electrum.desktop from terminal to see error message / actual problem.
But using
sudo/
su to run Ellectrum is strongly not recommend and it's bad practice.