Insert php code on "sharebar" plugin

Hello, I use the “sharebar” plugin.
It display sharebar with social network share button.
I would like to add custom php code on this sharebar but it doesn not work using the “plugin settings” in wp-admin.

I think I have to add the code directly on sharebar.php but I don’t know where…

Here the sharebar.php code : [removed]

thx.

Hello, I added php code creating a new button, but it does not work (usingthe plugin sett)
Where should I add this code to make it work ?
Maybe on sharebar.php but where exactly ?
Thx