It's the button that says OPTION.
Except on international keyboards, where the symbol is labeled ⌥
Not everyone's keyboard looks just like yours.
Right next to ....Open Apple.
Ahh, I see your problem. You're still using an Apple II series machine. No wonder.
In case you're wondering, Apple's new "Mac" line now has command keys, always labeled with the ⌘ symbol (sometimes, but not always, dual-labeled with the open-Apple symbol.)
Hope you get a newer computer soon...those fifteen-year-old Apples were solid, but they're showing their age now.