There is no option to create a new blog entry for the Better World with Arduino Competition.
Pressing submit an entry ends in page not found
or redireect to Add Question Or Discussion
So if you're not a member of a group, you should see this:
If in doubt, click to join the group
If you are a member of a group, you should see this:
I've just logged into the community impersonating your account (effectively logged in as you) and for some reason the ability to join the group was disabled, which also wouldn't have helped.
I have changed permissions on the group, so you should now be able to blog there as a standard user, you can now also join the group.