Interviewers often use project discussions to understand how a candidate thinks. They may ask what the objective was, what you personally owned, which decisions were difficult, what failed, and what you would change next time.
A useful structure is simple: context, responsibility, action, result, and learning. Avoid describing the entire team’s work as your own. Precision creates more credibility than exaggeration.
Be ready to go deeper technically or commercially depending on the role. If the project involved code, know the architecture and tradeoffs. If it involved marketing, know the audience, metrics, and reasoning.
The purpose is not to memorize a speech. It is to understand your own work well enough to discuss it naturally.