Update a ListView control on a different form

Hi everyone!

There's a 'small' problem with my program. I need to update a Listview control which is placed to an other form after clicking a button on my first form. Well... I googled a lot and found some advices how to solve that problem but unfortunately, nothing worked correctly. It is obvious that I have to reference controls which I'm calling but I'm not sure how to do that?

thanks in advance