I hope you all are aware that, Google Blogger or Blogspot does not have Table of content plugin like WordPress.
How to add table of contents in blogger?
Below is a short guide to add TOC in Blogger. You can also find a video tutorial here.
1. Log into your Blogger
2.Select Template or Theme and Click on “BACKUP” then Click on “EDIT HTML”.
3. Now search for the </head> and paste the below script just above the </head> tag.