BLE shield and PWM connection

I am working on a project for school. I bought an arduino mega 2560. And then attached a BLE shield from geeetech. With research on line it pretty much is a replica of the redbear BLE shield. I downloaded the software and got the boards communication with my iphone.

My problem is i bought a triac to vary the speed of a fan or use it as a dimmer. The triac card has a 5+, gnd, gate, and sync. The ble shield program has the ability to change the pin from input to PWM, servo, or output. Where would the wires fo to get the vary in voltage. If anyone cannhelp would be greatly appreciated.