The first version of Windows that was widely used was Windows 3.1, which used the Program Manager shell. While the Program Manager introduced the Macintosh-like icons and was a far better UI than the ancient pile of crap MS-DOS Executive that it replaced, using it quite frequently resulted in a slide puzzle-like game of managing the MDI windows.

Windows 95, Microsoft promised to bring up an all-new UI that was sleeker and far easier to use. Aas far as I'm concerned, they exceeded that expectation.

The Windows 95 splash screen, now with clouds and a loader bar! Well, not quite a loader bar.

The all-new Windows 95 desktop.

The first thing a Windows 3.1 user (or any user) would notice, there is now a bar at the bottom of the screen, along with a button marked Start. The next thing a 3.1 user would notice is the presence of completely 3D-controls like OS/2 made popular.
Another thing a Windows 3.1 user would notice is the presence of icons on the desktop. Previously the desktop space was reserved for minimized window icons.

This is the original retail release of Windows 95. Notice the lack of any Microsoft Internet Exploder, in fact the only piece of networking is the proprietary MicroSoft Network thing. The first version of Windows to bundle IE as a component was the OEM version of 95.

To launch programs in Windows 95 you must use the new Start Menu. You could do things the old fashioned way and use the run command, but why do that when you have this fancy GUI?

The start menu has actually been criticized very frequently. Having a constant set of options for every user is very useful in terms of giving support, since every single install will all be the same.
The problem is, the Programs menu was always different, and wasn't that easy to use. If you wanted to open up Paint, you would go to Start>Programs>Accessories>Paint. If you accidentally closed it you would have to do that all over again.

In an ideal world, you would place the program's main executable in the root of the programs menu. In practice, however, many programs still continued to do things the Windows 3.1 way and created program groups, often with complicated sub-hierarchies or filled with completely unnecessary shortcuts to things that would never be used.

If you were using a computer back in the '90s, you would mainly be using it to either create documents or play computer games.

Most people in 1995 still were just beginning to get their first computers, and as such they were used to the real-world way of handling documents.
In Windows 3.1, you would generally open a program, possibly open a file, enter some data, and then save the file to disk. This is not the way the real world works.
Windows 95 does things the way you would in the real world, by having you (generally) create a document file, click on that file which would subsequently open it in the program of your choice (or it's choice), enter some data, and then save the file. The Mac, among others, proved that this is the best way to do things.

The Windows 95 desktop is, in itself, a folder, and can hold files and other folders, unlike previous versions of Windows which were limited to just minimized programs. In fact minimized programs no longer appear on the desktop.
Drives attached to the computer have an icon in the My Computer folder. This helps better accomodate systems with thousands of partitions/mapped drives, unlike the traditional Macintosh way of placing drive icons right on the desktop. Also unlike the Mac, Microsoft has chosen to remain with the menu bars for each window scheme, rather than having a single bar at the top. Again, this accomodates systems with larger displays or billions of open windows, however the problem is that the desktop doesn't have a visible menu for doing any sort of file manipulation. The right-click context menu you see here exists for that sole reason, but this isn't as obvious as a file menu would be.

As you can also see, it is possible to create all kinds of different files, even by default. Software developers were encouraged to add templates for their programs, but in practice unfortunately few actually did.