First you have to empty the fridge, because when you move it the things inside could fall over. Move it away from the wall. Take care of the waterhose.
On the picture yoou see the bad clogged air louvers on the backside of my fridge. This is the filth from only THREE YEARS ! The air cant flow unhindered, thats very bad for the fridge.
When you open it, Be VERY careful, in the pipes is a flammable gas.