You can use arrow keys on your keyboard (or change that in options for something better like WASD), or (may have to be enabled in options) mouse panning where moving your cursor to the edge of the screen makes the camera move. Having said that, most people who play PA, and video games in general, avoid using Apple's mice because they are objectively worse than gaming mice for... gaming, and for me subjectively worse for everything else.
You got a problem. But no worry apple is better then ms. I'm sure they figure it out. Better ask this question at Apple.com Also you can rebind keys