Please remember one thing. Normally, when we train participants on leadership, we tend to quote very prominent worldwide leaders in politics, armed forces, industry, and so on.
However, please share with the participants that leadership occurs at the grassroots level or at the shop floor level. You should impress upon them that each of those leaders mentioned above had certain qualities. The participants should be able to identify these qualities and develop them over time—such as taking initiative, taking risks, showing empathy, rather than just showing how to do a job by doing it themselves and demonstrating to team members, taking suggestions from everybody before deciding, solving problems by sharing them with other team members, and walking the talk, among others.
There are excellent videos on leadership skills and team building on YouTube that should help them better understand the topic.
Additionally, incorporate a couple of games to illustrate the meaning of leadership.
Best wishes