I want to add to join form

In the join form I would like to add more check boxes and text and notification of automatic rejection by admin for failure to comply with requirements. Does anyone have an idea how to do this?

I have dolphin 7.0.8 that I would like to make changes to. I also would like to add a check box to terms of use forcing users to check box that they have read terms of use, in terms of use.

On Join form if the check box is not checked in terms of use, it would redirect user to terms of use to complete THE CHECK BOX

THIS APPLIES TO OTHER FIELDS ADDED TO JOIN FORM AS WELL.

check boxes and join form fields are relatively general, the automatic rejection will be a feat. 

 You can do all that in the Admin Profile Fields section I believe. Check that out, and you can setup fields as Mandatory. Means user must enter to continue.