The Amiga 500 has a very console-like experience for the most part when it comes to games. Treat DF0:, the internal drive, like you would the cartridge slot of a Super NES or a Sega Genesis. Just put your game into the internal drive, turn on the power and let the Amiga boot from it. :)
You can either:
- Power the machine off, insert your disk, then power the machine on. You'll see the screen cycle through a few shades of grey as the system runs some tests, then the game will start.
- Power the machine on with no disk inserted, wait, and insert your disk when you see the following:
Left: Amiga 500 'Workbench hand' screen. Right: Amiga 1200 'insert disk' screen.
This screen doesn't literally mean you have to insert Workbench, it means you can insert any bootable disk. Almost all Amiga games and software will boot from this screen, if you insert the disk into the internal drive.
If your Amiga boots directly to Workbench without showing an 'insert disk' screen, you may have an internal hard drive. This is a somewhat common accessory for the Amiga 600 and Amiga 1200. To boot up a game on an Amiga with a hard drive, you can insert the floppy disk while the power is off, and the Amiga should boot up off the floppy disk instead of the hard disk. Alternatively, you can insert your game disk while Workbench is running, wait until disk access has finished (wait for the LED to go out) then perform a soft reset by holding Ctrl+A+A. (These are the 'Amiga keys': two boldfaced A keys on the lower row of the keyboard.)
For games that support multiple floppy disk drives, such as The Secret of Monkey Island or Superfrog, first power off your computer, attach any drives you have available (use the small screws if they're there), then power on the machine. Insert Disk 1 into the internal drive and the game will start. Since Monkey Island comes on multiple disks, it will occasionally show a message asking you to insert a specific numbered disk into any drive. You can eject and swap disks during gameplay only when the game asks you to. Many games won't recognise a second drive. It's not a hardware fault: they're simply not programmed to use it. Some games specifically ask you to insert a disk in 'Drive DF0:' - that's the internal drive. If nothing happens when you put Disk 2 into the external drive when prompted in a game (wait several seconds first for the disk change to be acknowledged, or try pressing Fire or Space), try the internal drive instead.
There are very few Amiga games that run under the Workbench GUI in the same way you'd play Minesweeper under Windows. Most games expect full control of the computer, and skip Workbench entirely.
The few games that do allow installation, like simulations (Sim City comes to mind), strategies, wargames, do allow you to install the game to the hard drive, where you can launch it from Workbench from an icon like the 'Say' application. Check the manuals for these games for how to install them; every game is different, though most games that are installable show up as a disk icon in Workbench, containing an installer icon somewhere inside.