>>105891965
>Also, what's this red thing on my keyboard? Is it a mouse? Can it click?
I assume that's the red trackpoint on a Thinkpad. It's a mouse and I think it can click if you enable tap to click.

>Also what is the app center? How is it different from getting apps via apt-get command or just downloading programs?
It's just a graphical way of installing stuff, but you can use the command line if you prefer.

Also you mentioned emulators earlier. Ubuntu's Software app might not always be the best source for emulators. E.g. when I search for Dolphin in there (Gamecube/Wii emulator) it comes up with the Snap store version of Dolphin, which is an old release, and unofficial also. You can get the latest version of Dolphin by setting up their official Flatpak repo. Info is here: https://dolphin-emu.org/download/

But if setting up Flatpak is too much effort, you could try the Snap version if you want. I wouldn't use it myself, but it's an option. Or there might be dolphin-emu in Ubuntu's repos on your system, but it depends on which version of Ubuntu you're running.