organic group features implement into projects

I am using organic group . i want to use as:
any authenticated user can create group.
any member of group can add any content type(event,group post, article etc) into group
any member can join and leave the group.

some of thing are done by my side,but few thing like how to show link for add new group and add content type into group for authenticated user.

i am using custom theme.

Thanks in advanced