PMI has created a quick refresher course on Project kickoff.  Kickoff micro-course has two variants. Agile and Waterfall

It is a fun yet informative course with great graphics. 
I feel it is a great tool for beginners to start with Agile project management and expert to revise the concepts. For those who are preparing for the PMP 2021 exam, this small course can be a starting point for the Agile Journey.  

This micro-course is totally free from pmi.org. You will only need

to register on the PMI website.

Registration on PMI- https://idp.pmi.org/register
Kickoff Course landing page - https://www.perfectkickoff.com
For Kickoff micro-course - https://kickoff.pmi.org

Agile Kickoff micro-course has below chapters.

1. Introduction
2. Getting It Up And Running
3. Set The Vision & Get Aligned
4. Build Your Team
5. Set Up Your Team Room
6. Getting The Work Done
7. Harness The Magic Of The Sprint
8. Start Creating Your Backlog
9. Create User Stories
10. The Sprint Planning Meeting
11. The Daily Scrum
12. The Sprint Review
13. The Retrospective
14. Being Agile
15. Measuring The Madness
16. Release To Operations
17. Finish Up & Celebrate

Waterfall Kickoff micro-course has below chapters.

1. Introduction
2. Getting It Up And Running
3. Align People And Objectives
4. Planning Your Project Work
5. Know Your Stakeholders
6. Get A Grip On Project Requirements
7. Break Down The Work
8. Sequence The Work
9. Determine Who Does The Work
10. Create The Project Schedule
11. Know Your Risks & Create Mitigation Plans
12. Review The Plan With Your Sponsors
13. Getting The Work Done
14. Project Kick-off
15. Measure Project Success
16. Keep Track & Stay In Control
17. Stay Aligned With Key Stakeholders
18. Closing Your Project
19. Finish Up & Celebrate!

Select the course which you values the most of you. Both are equally great. I am using Agile practice in day to day life to I opt for the Agile micro-course variant.