No, I'm working blind, you have the unit in front of you.
Typical mounting convention is the attach slider rails to the furnace blower housing and furnace using screws to hold the blower housing in place.
Really can't say how many and/or where but, just study the engineering and it will come to you. I wouldn't expect any screws to be in the back where they would obviously not be accessable.
You may have to remove some wiring to get the required clearance to pull the blower housing out. If you do, just be sure to write down what wire came from where so you can hook it all back up when your done. A pic before you start dismantling would help but, I wouldn't depend on it 100%.