Understand how retrospectives can be used as a mechanism for process improvement in agile project.

Resprospectives are the team meetings or catch ups to look at the sprints retrospectively and identify the good things to celebrate, bad things to stop and the things to improve and get better as a team. In the PMI world we used to call it as a Lessons Learnt meeting.
It starts with inviting the whole team for a quick 30 minutes meeting by setting an expectation that feedback of all members in the team is equally important and action items coming out from this meeting would be implemented for the betterment of the project and the programme.
Team then comes to this meeting with an open mind. All team members are asked to write good and bad points on the postits and put them on the retrospective wall on the board.
Scrum master or anyone leading the retro would then work the whole team through the inputs and try to group them into logical categories
Team as a whole discuss these categories and try to find a common ground for action item e.g. it could be a commitment from development to do extra due diligence while adding fields and type lists on the screen instead of relying on a tester completely to test them properly
Scrum master then notes down all action items and track if the owner of the action items are working on implementing improvements based on the action items
In the next retrospective the whole team should see a measureable improvement in the team and its efficiency.