The solution is using Module Class Suffix. You can customize button, module content follow Module Class Suffix

E.g. Module Class Suffix: @bullhorn then:
- Class of button is 'fa-bullhorn'. If without @... the default is 'fa-pushpin'

Special positions is: sticky_left, stickey_right, notice, tool_bottom. You can use them for any module type. And to use, please go to Module Manager config your module to your desired postion.

You can disable by:

• Go to Administrator » Template Manager » Your_Template » Tab: Advanced » Use special positions » select: No for all special positions
• Go to Administrator » Module magager » Your_Module(by postion: sticky_left/stickey_right/notice/tool_bottom) » Status: Unpublish for that module