Replacing the underdash heater duct tubing for 67-72 C10 Non/AC trucks

[HeavyHauler]

I am going to replace or clean the underdash heater duct tubing on my 1968 Chevy C10. This truck is a non AC truck.

How difficult is it to to remove the heater duct and tubing on the 67-72 C10 trucks and does anybody have any tips on removing them or links to a video about them.

I havent been able to find any info and I havent even peaked under the dash yet to see what I am going to be dealing with. .