nevica wrote:Which Synaptics code are you referring to please?
The Raspbian image has a PM already installed - Aptitude.
If you don't have a root password set then you will need to start aptitude from a terminal session instead of the desktop menu.
sudo aptitude
(If you start by the desktop menu then Aptitude will ask for the root password which is not set by default in Raspbian, so you won't be able to install anything)
Aptitude is a text based menu system and is a bit cumbersome to use but not as bad as the command line commands.
I prefer the GUI based Synaptic PM. Install it with the following:
sudo apt-get install synaptic
Unless specified otherwise my response is based on the latest and fully updated RPiOS Buster w/ Desktop OS.