Extruder Calibrations

This week I have been trying to get my Geeetech A20M back up and online to do some easy printing. The first this I went to is DrVax videos. The first one that I tried to do is the Z-Offset. Then there was the one about Bed Leveling and then
Assitested Bed Leveling. After all that I was totally confused and then I found the video “3d Printer Calibration and Maintenance - PID and Extruder Calibrations” Now I am really confused.
I got thru the PID configuration and calibration OK. Then I started on the Extruder calibration. That didn’t go so well. I must admit that I am no math genius but trying to follow the video and apply it to my situation was very confusing.

I started with the M503 and copied the M92 X80.00 Y80.00 Z400.00 E114.94 for reference to the E114.94 setting. I started off with 114.94 X 100 = 11,494. Next, I marked off 120mm of filament and sent an M83 then a G93 E0 then a G1 E100 F100. The filament extruded and then I mismeasured the difference of leftover. It was 33mm now is where I get confused, I took 120-33=87. OK The big calculation: 87=(114.94x100) / 87 (((Is This Right?))) Doing that I get 132.1149. When I put that into the E132.12 and do another extruder calibration I get 45mm not excluded.

I am totally lost, confused, and frustrated. Can someone please explain it to me in terms that I can understand? I know I am old and get confused but that is about what I am going to have for lunch. Not trying to figure out how much filament goes thru the extruder.

Just take one step at a time and start at the beginning:

https://teachingtechyt.github.io/calibration.html

Good luck!