Newbie: Downloading apps to desktop

So, I have been using PC's for over a decade and I finally switched to an imac a few days ago...

I recently downloaded MoZilla Firefox and I got two files on my desktop. Mozilla and some other kind of weird file that I don't think I even need (what is this?) In the past, for PC's the file downloaded is usually a setup file. In this case, there was no install when I clicked on the downloaded file. It seemed to work right away. When I try to move the file to 'applications' it does not let me do it. Do I have to leave this on the desktop?

You can leave it on the desktop, but you should really store it in /Applications.
If the program is running, quit it. Then try to move the icon.

I believe I closed it and tried to move it, but it restricted me for some reason. When I get home, I can post the exact message it gave me. So there are no installs for mac programs??

The file you downloaded was a .dmg file. It is a white file with a hard drive icon. When you open that file it expands it to a Disk Image (Looks like a white hard drive on your desktop) inside of that disk image you will see the Mozilla Firefox application. Drag the application to your Applications folder. Once that is dragged over you can eject the disk image by dragging it to the trash, and trash the .dmg file you downloaded

i see... .DMG file that is correct... thanks for the help.. i'm definitely learning a lot everyday...

Here's a graphic representation of an older version of Firefox. After Firefox is loaded into the Applications folder, you can trash the files that are left, or keep the .dmg as a backup.