You want to add the oak chips to the secondary! You definitely don't want to boil them in your boil- you'd have tannin beer. Once fermentation has stopped, rack onto the oak chips in secondary. No need to sanitize them, especially if you're opening a new fresh package.
One ounce for 2-3 weeks or so should be about right. If you leave them too long, you'll have to age the beer longer. I oaked an Imperial Amber last year for 10 days (3 gallons with one ounce) and it took 5 months for it to age enough where it didn't overwhelm you with oak tannins. After those 5 months, though, it was heavenly!
Taste a small sample after 10 days. If it's not quite enough, leave it another 4 days. If it's a bit too much, but just a bit, it's perfect! That's the goal. If you love the flavor, that is ok too, but it'll fade and mellow with age, so you want just a hint too much.