Only the founder of your team can enter your team into a challenge.
The team founder (here on BOINCstats) is the person who is founder of the team in most projects. To check who is the team founder, find your team on the profiles pages
and go to the profile. The founder is listed there.
The team founder has a extra section in his BAM! menu (Team founder) and in that section he will find the Challenges. Once there everything is self explanatory.
The team founder is assigned by an automated process, he can't be set manually! If your team has a separate admin account then create a BAM! account for this admin as you would for a normal user (so same email and password). Include all projects but do not attach hosts to it or use any of the managing functions other than the team functions. It will not link to any stats, only to the team it is a member of and it will show as founder, so your team can participate in challenges.
Please do not PM, IM or email me for support (they will go unread/ignored). Use the forum for support.