If you have an iPhone or iPod touch, you can purchase and download the Keynote Remote application from the App Store and use it to control your slideshow. After you’ve purchased the Keynote Remote application, you must link it to your computer before you can use it. To do this, your iPhone or iPod touch and computer must be on the same Wi-Fi network.
You must open the Keynote slideshow document on your computer before you can begin to control it using the Keynote Remote.
Open Keynote on your computer and choose Keynote > Preferences.
Click Remote in the Preferences window and select “Enable iPhone and iPod touch Remotes.”
Click the Keynote Remote application icon on your iPhone or iPod touch.
On your iPhone or iPod touch, create a link to Keynote, following the instructions on the device.
A passcode appears.
In Keynote, click the link button next to the remote device that you want to pair with, and type the passcode into the window that opens in Keynote.
Close Keynote preferences.