Making a play button from a custom renderer tabbed page

Hi!

i am trying to change the middle button of this project i found on github to make a small radio app, https://github.com/smetlov/XamarinFormsAndroidBottomMenu

So far i changed the bottom bar color, added 3 buttons (Home, Play, Radio) and now i am fighting with making the Play button a button that can change its icon and make a singleton play some music.

If someone could give me a hand here i would really appreciate it!.

(the original project has 2 buttons, i added a third page and the second one act as a button that has to change its graphic, if i knew how).