24 days late

Hi i know i am 24 days late but was tracking my weight so on jan 1 I was 92.8kg today I am 91.1 kg I hope I can still join the challenge I just don't know how to add a pic. my total goal weight is between 70kg and 65kg depending how i look.

Can someone please explain the challenge to me and how it works and what I should do.

thanks