i have a problem making my entire screen shown, which is a problem when i want to show other people how to do anything in ubuntu.
i can choose between showing a part of my screen, or another part, but still not the entire screen.
menu - system - preferences - monitors
(i have nVIDEA graphics, with nVIDEA driver)
It appears that your graphics driver does not support the necessary extensions to use this tool. Do you want to use your graphics driver vendor's tool instead?
and i get the chance to say yes or no.
yes for nVIDEA driver configuration and no for Ubuntu's inbuilt (whatever it is) in which i can configure the size of whats shown on the projector.
how do i show my entire desktop?
From the output you get I guess that you have not yet installed the proprietary Nvidia divers. The open source driver is nouveau. After installing the vendor drivers you will have a Nvidia configuration tool in your System section that allows "cloning" of your display:
Open nvidia-settings and choose "XServer-Display-Configuration". Your projector should automatically be detected when choosing "Detect Displays". In the configuration part you should be able to choose "Clone Display".