Karen, don't feel dumb!
(I know, easy to say...but that link doesn't work for me either)

Assuming your pool guy's estimation of your pool volume is correct, there's a truth you'll have to face right now: you're going to need a whole bunch of chlorine to get going. Partially due to the size of your pool, but also due to the high CYA. Brace yourself, with that size pool, and with the guidance of Ben's Best Guess CYA chart indicating a need for 25 ppm chlorine level to shock, you'll need 20 gallons of Clorox Ultra laundry bleach (6% sodium hypochlorite). And that's just the initial shock. You'll have to sustain that 25 ppm for a couple days to clear the algae. Quite a task!

First, I think it would be a big help to lower your CYA level which can only be done by draining half the water and refilling to dilute it. This will reduce the amount of chlorine you'll need.

Next, I think this might be a situation where you might consider buying the higher concentration chlorine available at pool stores. It's typically 10 or 12.5%. Double the concentration, halve the dosage. I've recently found I can buy it at a local family-run pool place and it's actually cheaper than Clorox.

I hope Mike comes along with the link to his bleachcalc (Mods: can't this be a sticky somewhere?) because it's a Godsend for finding all your chemical needs.

Anyway, I'm not an expert, just a veteran BBB user. I hope a real expert can comment on my advice because that's what I'd do in your shoes (actually I think I'd jump for joy at having such a pool too!). Hope you don't have to heat it too.

C.