2D Space Shooter Tutorial : Ship Movement

Hey guys! Im new to unity but what ive been doing so far ive been having a lot offun. Im currently working on a 2d game based off of the tutorials for 2d space shooter game. My problem is after writing the script for movement exactly like it shows in the tutorial, my ship wont move at all no matter what button i push. Is there a way to remedy this? Please help! Thank you :)