Hi! The icons used there are FontAwesome icons. You could replace it with any of the available icons from that pack - like “icon: beer” or “icon: rocket” etc., as long as it’s from the FontAwesome pack. I’m not sure how you’d easily use your own custom icon however, sorry.
Thank you! This information was very usefull. Mayby I can find some icons that i can use in my projekt. But if somebody know how can I use my own icon i will be grateful