Sounds like a 3 gallon recipe to me. Here's how I would proceed:
Fill the sink with hot water and put the cans of extract into it for 20 minutes.
Meanwhile, sanitize everything you're going to use with your sanitizer of choice (ask if you're not sure what this step means). Also, rehydrate the yeast with a cup of CLEAN, warm (80 degrees F) water.
Fill your brew pot with about 3.25 gallons of water, open the cans, add the extract, and stir thoroughly.
Bring the brew pot mixture (now officially called wort) to a boil, and boil uncovered for 20 minutes (I read that EDME's kits usually call for a 20 minute boil). Watch carefully for boil-overs.
While boiling, fill the sink with ice water. As soon as you are finished boiling, put the brew pot in the ice water to begin cooling the wort. Swirl the pot around in the ice bath from time to time to speed the cooling process.
When the temperature of the wort is below 80 degrees F, pour/siphon it into your sanitized fermenter, and dump the rehydrated yeast mixture into it. Don't bother stirring it. Cap with the fermenter lid/stopper and an airlock.
Hopefully that answers questions for you rather than creating them.