I had Vivaldi on this computer when it ran 16.04. After installing Focal, I downloaded the browser. When I click on install, an Ubuntu Software window tells me:
Unable to install vivaldi-stable:
E: Could not get lock/var/lib/dpkg/lock-frontend. It is held
by process 4318 (synaptic).
I don't know how to find that in Synaptic. (Software is up to date.) I am inexperienced with computers and often have difficulty following instructions. A detailed step-by-step solution would be appreciated.
