[Help with using a Duncan Automatic Teacher-Plus Kiln]

Okay, thank you! Do I need to warm up the kiln before using it or do I load it and do the process you explained and then prop open the lid after the kiln shuts off? On some older kilns, I’ve found (from YouTube videos) that the people slightly prop open the kiln and set it on low for several hours with the peepholes open. Any advice for this part? 

[Help with using a Duncan Automatic Teacher-Plus Kiln]

Hello folks! I received a Duncan kiln from a family member about 7 years ago and was never taught how to use it. I attempted to figure it out on my own, but gave up because I was having too much trouble with it. I have never operated a kiln on my own- only seen electric kilns in use. 

Has anyone operated this particular kiln (DA820-2), and if so, could you answer a few questions for me?

• I believe I was having trouble because I did not have any pyrometric cone/bar things to turn off the kiln when it reached the right temp (clearly I'm a newbie). In the manual I have for my kiln, it says I need 'ASD' cones.  If my kiln fires to Cone 8, which cone of pyrometric bars do I need ? Does it always depend on the clay's cone?
• Where do I place these ^ cones when I have them? Is there a hole in the bars that slides onto the knob on the inside of the kiln wall?
• Do I need to have witness cones + the ASD cones? 
• After each firing, do I need to have new witness cones? 

Thank you!!

Natania