Ok to answer your questions, but just a overview, if you need to know more then please ask
gnome and kde
These are displays for linux, allowing you to see things in images, or environments, they are actually far more detailed than that, but for simplistic states, it shows files and folders and file management. They are actually 2 different things but can be used or offered together
Debian
This is the type of linux as a base source, it was named after the couple Debra and Ian, who took the linux system and made it more user friendly, they are no longer involved but a team of developers continue the work. Ubuntu is based on debian, and other linux versions are based on the changes ubuntu makes to give you a windows like environment, bit like icing on a cake.
Ubuntu like many linux environments offer a software centre a repository where you can download and install games in safety. Its like the play store on your phone or tablet. There are many games available in different groups.
change ubuntu to gnome and cinnamon
Here is a detailed guide on our own site
Ian and his wife Deborah took linux code and installed different components to create debian, after he stepped away from the project others in the team have maintained it and added other components to create the debian you see now.
Canonical is the owners and developers of ubuntu, they take the latest release, add or change content to form ubuntu.
Other groups such as linux mint take both versions and again make changes to form mint.
Software developers work on code creation and use different tools to arrive at the product you download and install.
Steam
This is not available in the normal repository so you need to do the following
Last time I installed steam on a “vanilla” Ubuntu - it was part of the default REPO… Didn’t have to download anything.
Ubuntu based Pop!_OS also has it in its default repo…
I haven’t tried to use any GUI package manager to install Steam (Pop! shop is a bit useless and often broken) - 99.9999% of the time when I install something from a repo (instead of via “dpkg -i packagename.deb” from a downloaded DEB file) I do it via the terminal with “apt install packagename”… As a rule I NEVER add extra repos or PPA - but something do that anyway - like Brave Browser…
Steam just seems to work… Note : you can only install FREE to play or games you own on Steam!
If you’re trying to install Ubuntu on an 8 GB thumb drive - you certainly WILL NOT have room for Steam - never mind any games.
The one for ubuntu is maintained by the supplier of ubuntu which is Canonical so it is not the same as for other software. But in general terms most have similar popular things inside. Such as web browser, art programs, games etc
Vanilla ubuntu is just a name for the system you download and install to create your ubuntu system, it refers to its original state with no changes. It is then modified to create lubuntu, kubuntu etc…
Yeah - by “Vanilla Ubuntu” I meant Ubuntu e.g. 22, 24.04 24.10 et cetera with the default Gnome 4x desktop environment that you download from Canonical…