Mautic website download page button style

How can I put the animating icon on download button like you have on your Mautic download page when you press the button? I want to replace button text with rotating refresh icon.

(Link:https://www.mautic.org/download)

How can I put the animating icon on download button like you have on your Mautic download page when you press the button? I want to replace button text with rotating refresh icon.
(Link:https://www.mautic.org/download)