By the way, can anyone tell me how to join this campaign?
Read the 1st Post of this thread, everything is well described. You should have to apply first, if they accept you, you will get message from campaign manager.
I did that for other campaigns, so why didn't they accept me?
What's wrong with them?
If you didn't received private message here from Kapokala or Carollzinha a week after your application then you're probably not accepted. Though I can't find your application on this thread, you can check the op or the posts above and follow that format and post your application.