Schedule for video chats
Are you signed up on a team? I think the deadline was Wednesday to sign up. Go to your team's page. List of teams
To get credit once you correct a suggestion, click on the "challenge" link in the large green box at the top of the page (it's there after you make the edit and submit the change.) On the next page that comes up, click on the "status" button next to the suggestion corrected. On the next page, mark it corrected and select a phrase saying what you did and submit. You'll get credit. At the top of the last page I mentioned, you can click on the 2019 Clean-a-Thon link to see your teams scores, your own personal scores, etc.
I am not sure where the others are seeing a Green Challenge box that others are referring to. You should be hitting the Suggest box when you see the list of suggestions and the suggest box on the far right. When Suggest Page is shown, you have the profile to be updated and can update the suggestion from there, as well as see the other suggestions for that profile.
https://www.wikitree.com/wiki/Spring_Clean-a-Thon_Tutorial
That should give you help on how to proceed