Configuring Greetings Workflow - GitHub Actions

greetings.yml

name: Greetings

on: [pull_request, issues]

jobs:
  greeting:
    runs-on: ubuntu-latest
    permissions:
      issues: write
      pull-requests: write
    steps:
    - uses: actions/first-interaction@v1
      with:
        repo-token: ${{ secrets.GITHUB_TOKEN }}
        issue-message: 'Hey, @${{ github.actor }} welcome to this repository.🎊 Thank you so much for taking the time to point this out.🙌'
        pr-message: 'Hey, @${{ github.actor }} welcome to this repository.🎊 Thank you so much for taking the effort to make our project better! 🙌 Keep making such awesome contributions!'

how to get the GITHUB_TOKEN, and where to put it? @salikadave