Using Custom Icon for in place of the button

Hi, I am trying to use this awesome plugin in my website https://risheshworgroup.com but I don’t want to use different buttons that what I available for open and close with a title of possible (of I can write the title in the button itself and use it). Any way I use my own button for this?

Thanks in advance.

The page I need help with: [log in to see the link]