Slow, step-by-step instructions on hard carding. This is the way I've done it for years, it may not be the only way, but if you're struggling to get decent rolags why not give it a go!
Thanks to LJ S, I just pulled these very useful timing notes from the comments below.
6:00 First switch from one carder to the other
7:42 for the next switch
9:00 to start the final rolag