Specifically I followed the instructions to have the DLL file (aka assembly) written out to c:\inetpub\wwwroot\bin. This folder is there in my machine and the build put the file there without any trouble. The correct location of the file on my machine is:
Also, when it was time to edit the web.config file it was not in the folder specified in the video (c:\inetpub\wwwroot). Instead the proper folder to find the file to edit is:
Like some others I did a search for all instances of web.config in the c:\inetpub\wwwroot path and modified multiple instances of the file. It wasn't until I put the actual DLL file in the correct bin folder that the web part actually showed up for me.
While I was frustrated by the fact that my web part wasn't working when trying to follow along with an extremely elementary exercise, I have to (grudgingly) admit that I learned more about the whole process by having to repeat the steps multiple time and beat my head against the wall in frustration.