Desktops
Gnome
Gnome its not the typical desktop environment that you are familiar with, there is no actual desktop just a pretty background image.


There are no icons or shortcuts to click and to get to your applications you click on Activities or hit the Windows/Super key more» .
Mate
When Gnome 3 went all shell like in 2011 some developers disagreed with that direction and created a new desktop environment Mate continuing on from Gnome 2. This is called Forking, thankfully in the Linux community there is no mention of Knifing. The result is a straight forward desktop environment and a better option for a Linux Newbie to start with.

By default Mate has two panels one on top and one on the bottom.
The top panel has, starting from left to right: an Applications Menu with everything listed where you expect it i.e. LibreOffice under Office.

Drag an applications icon to the Desktop to create a shortcut there or to the top panel to create a single click to launch the application from there. Brill for all your favourite applications.

The Places menu is a quick way to go to a specific location or to go back to a recent document.

The System Menu is where you go to tweak Mate, get help and Lock the Screen/Log Off/Shut down.

Click on the Date and Time at the right of the top panel to get a handy Calendar, click again to hide it.
Beside the Calendar is the NetworkManager Applet which will prompt you to sign into a wireless network when they become available and a Speaker Icon that controls the volume, right click this icon to go to Sound Preferences.

Mate application windows act similar to Microsoft Windows.
- Double Click the title bar to toggle between Max and Smaller.
- Drag the title bar to the middle of the top bar to Maximize.
- Drag the title bar to the sides to get half a window.
- Drag to the Left or Right of the top bar to get a quarter of a window there.
- Drag to the Left or Right of the bottom bar to get a quarter of window there.
Mate like most Linux desktop environments (and Windows 10) uses a concept called Workspaces aka Virtual Desktops which are copies of the same desktop: same menus, shortcuts, etc and is very convenient when running multiple applications.
For instance on Workspace One you have a full screen Firefox watching a YouTube Video and want to open another application, so rather then mess with Firefox, you switch to Workspace 2 and work from there instead.
This is the function of the Bottom Panel which on the left contains a list of running applications on the current workspace.

Mate by default has four workspaces and in Bottom Panel on the right is the Workspace Switcher where the Workspaces are represented by four rectangles and open windows are shown as miniature thumbnails.
You Click on that Workspace Rectangle to move there, better still use the Shortcut Key Ctrl+Alt+Right Arrow to move from Left to Right between Workspaces or Ctrl+Alt+Left Arrow to move in the opposite direction.
To move an application to a different workspace..
- Right Click its title bar and choose which workspace to move to.
- Or Drag that applications tiny thumbnail from one workspace box to another
- Or Right Click on the applications name on the Bottom Toolbar and Choose or Drag that the name to another Workspace Box.
It's easy to customize the panels, one item I always add to the top panel is the Window Selector. I Right Clicked the Top Panel and clicked Add to Panel.... In the Add to Panel box I scrolled down to Window Selector and Dragged it over beside the Speaker Icon.

Clicking on the Windows Selector Icon will give you a list of running applications grouped by their workspaces. Click on the application name to go to it or Drag the name down to another workspace rectangle and move it there.

When you are using Mate Click on System»Help to get the Desktop User Guide for more info.
There are many more desktop environments for Linux, want to install Linux on an older PC then check out Xfce and LXDE both are lightweight, low resource usage Desktops.
Or if you really like eye candy and have a decent PC to install Linux on, check out KDE.