I had trouble adding "share this" buttons to my Ghost blogs' Casper theme.
Presumably editing default.hbs would work, but I didn't want to modify a theme for basic rough draft sites.
Addthis.com's instructions mostly didn't work. Ghost isn't explicitly supported. The HTML website instructions partly worked. The AMP instructions didn't work.
I found a way to add the inline sharing buttons manually to each post. I can occasionally batch this mindless task when I need a brain break. I prefer inline to floating, anyway.
(Maybe I'll get tired of doing that eventually, and modify the theme instead. At that point I'll have accepted the necessity of doing things the smart way, and won't forget about the repo when it's time to upgrade the theme.)
Here's how to add inline addthis.com share buttons to a Ghost post:
Get the code -> An HTML Website
- Copy the first codebox into Ghost's Code Injection -> Header box. Hit Save.
- Copy the second codebox into Ghost's post composition window -> click plus -> HTML. Append a tag to indent properly afterward.