I cloned the GitHub repository to my computer:

git clone git@github.com:pjacklam/p5-Math-Polynomial-Chebyshev.git

Ran the tests locally:

cpanm --installdeps .
perl Makefile.PL
make
make test

Created a branch

git checkout -b ci

Copied the perl.yml file from the try-github-actions repository.

I saved a copy of the file here so even if the file changes in the future you'll be able to find the original copy:

examples/chebyshev-ci.yml

name: Perl

on:
  push:
  pull_request:

jobs:
  test:
    strategy:
      fail-fast: false
      matrix:
        runner: [ubuntu-latest, macos-latest, windows-latest]
        perl: [ '5.32' ]

    runs-on: ${{matrix.runner}}
    name: OS ${{matrix.runner}} Perl ${{matrix.perl}}

    steps:
    - uses: actions/checkout@v2

    - name: Set up perl
      uses: shogo82148/actions-setup-perl@v1
      with:
          perl-version: ${{ matrix.perl }}
          distribution: ${{ ( startsWith( matrix.runner, 'windows-' ) && 'strawberry' ) || 'default' }}

    - name: Show Perl Version
      run: |
        perl -v

    - name: Install Modules
      run: |
        cpanm -v
        cpanm --installdeps .

    - name: Run tests
      run: |
        perl Makefile.PL
        make
        make test

    - name: Show Errors
      if:  ${{ failure() && startsWith( matrix.runner, 'windows-')}}
      run: |
         ls -l C:/Users/
         ls -l C:/Users/RUNNER~1/
         cat C:/Users/runneradmin/.cpanm/work/*/build.log

Then had to fork the original repository on GitHub so I will be able to push out my changes.

git remote add fork git@github.com:szabgab/p5-Math-Polynomial-Chebyshev.git
git remote -v

Then pushed it out the changes to my repository.

git push --set-upstream fork ci

Chyecked the Actions tab to see if everything works fine.

Finally I sent a pull-request asking the author to accept these changes.