more on overlapping

[thescottie.com]

I worked a scrimmage Saturday, and being my first real workout as an official, most of the day's calls were rather simple to make. But I am a little confused about the overlapping.

I had read earlier where someone has an explanation via PowerPoint. Could I get that please?

One thing that really killed me was, it being a scrimmage, I had no lineup card and substitutions were made very liberally (the "games" were 20 minutes running clock with no score kept). It was difficult for me to tell who was out of position on the serve, who my front row players were due to the strange alignments, etc.

If anyone has anything to help me out, please e-mail it! Thank you!