Windows:
1 - Click a download link
2 - Yes, I'm sure
3 - Run
4 - Next, Next, Next, Finish
5 - Delete the setup file
OS X:
1 - Click a download link
2 - Yes, I'm sure
3 - Open a finder window
4 - Open .dmg file, and it mounts
5 - Open the mounted image
6 - Run the installer (or drag it somewhere, depending on the app)
7 - Continue, Continue, Finish
8 - Unmount the image
9 - Delete the .dmg file