Replacing AC/Heater Fan Switch

[LCato]

I recently purchased a 1970 C10 with Air Conditioning and now I’m beginning to address a few minor issues. The current AC/Heater Fan switch had a little “melt down” prior to my ownership and isn’t working, so I’ve picked up a replacement switch I need to install. I’m not sure if I need to remove the entire Temp Control Assembly and/or other under-the-dash "stuff" to swap out the switch... or if there is a better way? Any guidance on the best way and recommended steps to accomplish this task would be greatly appreciated! I’m a newbie at this so don’t hold back on the details!