blog-by-tag Layout does not exist

[shashank-on-codehunt]

was following Introduction link
where the section for tags says

Example /tag/mytag.md:

layout: blog-by-tag
tag: mytag
permalink: /tag/mytag/

however seems like layout for blog-by-tag is not available

while generating for following error

Generating... 
       Jekyll Feed: Generating feed for posts
     Build Warning: Layout 'blog-by-tag' requested in tag/tips.md does not exist.

using free version ( not sure if this is the pre-requisiste)

along with that noticed Step 3, 4 not working properly

[shashank-on-codehunt]

Although currently i did a workaround commit link here

however later realized that would make entire process very repetitive e.g. commit here , leading to more prone for error.