How do you remove heater core from freightliner 2005 coronado under bunk?

Well I have a 2003 Columbia and mine is in a little black box with the blower in it..

1- I disconected all the hardnes

2- removed 4 bolts that hold the blower and pulled out the blower

3-I ONLY FIND ONE SCREW AND REMOVED

4- Now iT was verry challenging to pull out the cover but some how I succeeded puling out

5-Went outside open the hood close the valves that feed

6-unplug both hoses from underneath the bunk

7- back in the cab and unscrew the bolt that hold the heater core and the lines and simply pull out

8- pull out the heater core and put your new one in it mine cost me $53 from freight liner

9-put back in connect the

lines ..and there you go if u can put the cover back on it

10- because I am having hard time to put that cover back on it.

Note; I am not a mechanic but I always try now any one who can tell what from here..bring it on..dont shy..have fun..