Installing FBO Advance Plate ...help

I started this morning, following the instruction on his web site but got stuck. I can not find how to get the top shaft off. His instructions says there is a clip or screw to remove....can not find either one.

This is a MP electronic advance distributor made by Mallory for MP




Mopar Distributor Tuning J685S

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I like it
Set up your distributor without a distributor machine - nice.
I am confident that this method is not near as precise, non the less it will get you there with some trial and error.
Distributor P/N?