What is a confidential IPO and how do you participate in it?

What is a confidential IPO and is general public allowed to participate in it?

Lately there have been a lot of confidential IPOs. A recent example being the Duck Creek Technologies IPO. I try to follow the IPOs closely and I didn’t see this one show up for participation through normal channels on E-Trade, or probably I missed it. It just showed up directly for trading on August 14.

Here is how the news reads (Duck Creek Technologies Prices Initial Public Offering):

BOSTON, Aug. 13, 2020 — Duck Creek Technologies, Inc. (“Duck Creek”), a provider of SaaS-delivered enterprise software to the property and casualty (“P&C”) insurance industry, announced today the pricing of its initial public offering of 15,000,000 shares of its common stock at a price of $27.00 per share. The shares are expected to begin trading on the Nasdaq Global Select Market on August 14, 2020 under the symbol “DCT.” The offering is expected to close on August 18, 2020 subject to customary closing conditions. […]

How can offering close on August 18 at $27 if the stock is already trading on August 14 at $44.50?

Further googling on the subject shows that the company filed for a confidential IPO.