how do i play?
You need to download the file, but you also need an Atari 2600 emulator, for example Stella, you need to open the file with Stella.
Is emulator no good?
how to go to stella?
just google "stella emulator"
Oh & How do you Make Atari Games
With dasm assembler. You can also do them with batari Basic. There are tutorials in the web. You also can ask in atariage.com forums.