Task 1

Split commit with subject 'abc: Add a b c files'
into 3 comits each commit adding just one file.

This means will end up with 3 commits:

a: Add a file
b: Add b file
c: Add c file

Create a pull request with the commits

Task 2

Split each of the 3 above commits into multiple commits
each commit adding just one line.

For commit 'a: Add a file' you will end up with 3 more commits

a: add line 1
a: add line 2
a: add line 3

Create a pull request with the commits