You both can join challenges at the Starting of months in most cases. Just mention the admin and ask them to add you. I think so, it’s the case.
After that you just need to tell your daily weekly and monthly progress in most cases by just replying on the topic.
If any query, you can simply personally message the admin by clicking on his profile where you will get the option to message them. All are friendly here don’t worry.
Read the rules of each challenge because if you win you will get points. All the best bro these challenges are one of the best you can get to motivate yourself, saying by my personal experience though I am new.