Avocado ripeness??

We have a Haas Avocado which is finally producing some good sized fruits. My question is How long after picking should they ripen?
How do I know when to pick them?
Thanks for any help you may have.

http://www.ucavo.ucr.edu/General/Maturity.html Hope this doesn't confuse you as much as it does me

Another interesting site http://www.crfg.org/pubs/ff/avocado.html

Try this site - it's pretty straightforward: http://ceventura.ucdavis.edu/ben/avo_handbook/harvesting/pick.htm
Interesting subject! I live in avocado land but don't have any trees myself.