Meaning of Automatic Conversion in Series AA TermSheet

There is a clause Automatic Converstion in Series AA termsheet of Y-Combinator which says

Each share of Preferred will automatically convert into common stock,
at the then applicable conversion rate, upon (i) the closing of a
firmly underwritten public offering of common stock, or (ii) the
consent of the holders of at least a majority of the then outstanding
shares of Preferred.

1. at the then applicable conversion rate - What decides the applicable conversion rate, any pointers to few cases may help?
2. firmly underwritten public offering of common stock
3. then outstanding shares of Preferred.

(1) Conversion Rate Under the barebones AA docs, the idea is that if there's a 2-for-1 stock split of the common shares, then you should get twice as many common shares on conversion. The rate is equal to the price originally paid divided by something called the "conversion price," which gets cut in half, or a third, or whatever, on a stock split. It's a defined term in the Certificate.

(2) A Firm Commitment Underwriting is when the underwriter (approximately) agrees to buy, and then attempt to resell, all the shares issued by the company in an IPO (or other public offering). "of common stock" means that the company is selling common, not preferred stock in the offering.

(3) Two types of stock: Common and Preferred. Investors typically get preferred stock. The idea here is that investors holding a majority of the Preferred Shares can force the preferred shares to convert to common. Why a majority and not unanimous? Because unanimous means that a single small investor might be able to hold up a deal.