Hello!
Welcome to Linux Lite!
This might be in the manual, but I'm not a 'RTFM' kind of guy, so here you go...
The Install/Remove Software icon runs a program called Synaptic Package Manager. You can run Synaptic by
selecting Menu > Run Program and typing
gksu synaptic
in the long rectangular box. If checked, uncheck the 'Run in Terminal' box. A window will appear to type in the sudo (root) password.
Additionally, you can use Lite Software Center to install programs (Menu > System > Lite Software Center). This assumes your icon for this is there.
A third option is simply opening a terminal (CTRL-ALT-T) and typing
Code:
sudo apt-get install <package name>
to install, or remove software with
Code:
sudo apt-get remove <package name>
All Synaptic is just a GUI for apt, to make things easier.
If you're missing a LOT of icons, a reinstall might be in order...
73 DE N4RPS
Rob