I made a circuit that provided the H-Bridge functionality to the linear actuator, by using 2 relay modules. I connected the together using the following schematic and connected their signal pins to the Arduino's IO pins. 

Programmed the Arduino to interpret Channel 4's inputs as the signal for moving the snowplow arm by sending the D11 or D12 digital IO signal to the relay modules. I hope that a circuit like this one is able to help anyone else having the same design problems in the future.