"Eat the apple!"
The second way?
There is no second way. It's just that if you're talking to more than one person (or talking to one person with respect [the Dutch U]), you add "-(y)in" to the "regular" imperative.
Yap! → Yapın!
Söyle! → Söyleyin!
"Ye" is just an exception; it's not "yeyin" but "yiyin!".
The verb "Demek" (to tell), for instance, which always follows the same format as "yemek" is regular in this case: we write "Deyin!" (although it's pronounced 'diyin').