‘Help people’ would be better than ‘make people’, you can help someone to understand something but can’t ‘make’ them understand it. Maybe ‘....understand what eco-friendly means’ or ‘.....what is meant by ‘eco-friendly’’ would work better. It would be useful to follow this with an explanation of what the activity was.

I think the noun "activity" is a little strange, what do you mean by it? Maybe a more specific noun could work. A meeting? A conference? A workshop?