Once an IPO is announced, you must submit an IOI specifying the maximum number of shares you wish to buy.

If you did not receive an allotment, you can buy shares on the stock exchange after the "opening print".

Real-time order books (Level 2) show the depth of buy and sell interest, which can help you time an entry during the first few minutes of high volatility. Key Risks & Considerations how to buy ipo stock on first day: step-by-step - Bitget

On the "pricing night" (the evening before listing), you must confirm your order. Shares are then allotted based on demand; you may receive all, some, or none of your requested shares. 2. Buy on Listing Day (Secondary Market)

In the U.S. (NYSE/NASDAQ), trading often doesn't start exactly at 9:30 AM ET. A price discovery process or "opening auction" occurs first to determine the first trade price.

This is the only way to buy shares at the fixed before they begin trading publicly.