Hi @María Antonieta Martínez Morales
Welcome to Microsoft Q&A! Thanks for posting the question.
You need to first join the challenge from the page.
After joining you will see the "Start Learning" page which you have to complete the collection to complete the challenge.
Also, check the FAQ at the bottom of the page.
Please let me know if you have any other questions.
Thanks
Saurabh
Please 'Accept as answer' and Upvote if it helped so that it can help others in the community looking for help on similar topics.