● Enable the LikeBtn module.
● Configure the text formats (Filtered HTML and Full HTML) so the LikeBtn shortcodes filter is enabled through "Home » Administration » Configuration » Content authoring » Text formats" (admin/config/content/formats). Make LikeBtn shortcodes filter the last filter in the "Filter processing order" list.
● Use the following shortcode to insert the Like Button inside the node content: [likebtn]
● You can pass Like button settings as parameters in the shortcode:
[likebtn style="large"]

If identifier parameter is not specified, node ID is used. Use space to separate parameters, do not use commas or any other characters.