Understanding Recovery and Removal in TimeQuest

Hello, I'm new here. Thank you for your posting. I'm carefully reviewing the document above. I'm confused from the outset. So please help me to understand. On page 1, I read:

we have two clocks with the same period, 10ns. this results is a setup requirement of 10ns, and a hold requirement of 0ns.

Let's focus narrowly on the setup requirement at first for my benefit. When I think of a "setup requirement", I envision it applying to a D flip-flop with a clock input. The setup time then is the minimum time the signal on the D input must be static prior to the registering edge of the clock input. Given this, I'm not quite sure how to follow you or conclude as you do in the italicized excerpt above.

I hope you can bear with me. I appreciate your patience. :)