Firefox, Gimp, Openoffice

I am a recent switcher, running 24" imac with 2.8ghz core 2 duo, os X 10.5.7, I like the machine, a lot of things remind me of linux, which I think made getting used to it a little easier. I have had a few stumpers, here's my latest one--

I downloaded Firefox, Gimp, and Openoffice from Open Source Mac - Free Mac software, all open-source, all OS X.. I can find gimp in the finder, and initially I had Firefox, and Openoffice, and ran both of them, but now I can't find them anywhere! Does this machine have a "File explorer?" I haven't been able to find anything of the sort.

When you download apps, they typically come in the form of a .dmg file

When opened this creates a virual disk in which you can see the application, you can even run the app off the virtual drive but it will unmount when you shutdown.

Make sure you copy apps in to the Applications folder, and from there you can also drag the icon from Applications to the Dock to create a shortcut

Once they are safely in the Applications folder you will always have access to them

How to Install Software from DMG Files on a Mac

Most Mac programs are distributed in DMG format (disk image files). This concept is somewhat unique to the Mac. Basically, when you open a DMG file, the OS mounts that file as a virtual disk drive on your desktop. Interacting with it is very similar to inserting a disc in the optical drive or connecting an external hard disk.

Since many Mac programs are self-contained, installing the software is usually as simple as dragging the program icon from the virtual disk to the Applications folder. At that point, you may eject the virtual disk by dragging it to the trash can.

My guess is that you were running these applications directly from the virtual disk, and since you ejected that disk (either willingly or by rebooting the machine), it appears that the program is no longer available.

Thanks for the quick replies. Well I'll re-download 'em, and move them to applications before I shutdown again. You guys described exactly what I did.