I'm trying to get the rear axle off but how do I get the shocks off? Do I simply have to remove the nut on the bottom? I tried loosening it but the entire shock turned with it.

 

One hand on shock (to keep from spinning), one hand turning rachet/wrench to get lower nut off.
Some shocks have a squared up tit on the very end so you can put one wrench on the nut and another on the shock itself if your hand can't do it.
Or you could just use an impact like me

Then push up to compress the shock and pop it out of the lower spring mounts.

 

lol, yep, I was just getting on to say nevermind. I managed to get one off but the other is so tight the shock slips in my hand or twists my hand. but ya, I love impact drills

 

You can use a pipe wrench to hold the shock while you use a socket/wrench to turn the nut