I have a 1966, 289, 2 barrel carb. I need to set the points gap.

What is the points gap setting?
Whats the procedure to set the points gap?

I've looked for step by step instructions but can't find anything.

Do I need to worry about TDC?
Do I need to rotate anything in order to set the gap?
Is the gap set more than once?

Thanks in advance.