During the Project Management during in which process the Kick-off meeting started?

This is the first meeting with project team and clients to understand common objective of project and to discuss other project planning activities.

The kick off meeting is usually held after the planning is complete and the project is ready to be executed

At the end of the PLANNING phase.

This is the first meeting of Project team to discuss the path of project.

Sooner or on the day that the project Execution phase formally started. Considering that all elements at Initiating and Planning phase is already completed prior for Execution phase start up.

In most cases at construction industry, this is usually held on Execution phase formally started.

Setting the Agenda

it should clearly decide what items are going to discuss in the meeting.