Since you are new to RightNow as well as to this Community I would like to welcome you to the RightNow world.
Now, in this forum you can post the queries under user tab or developer tab (there are separate discussion forums as per your role). Idea Lab is for proposing functionalities which are not currently available in RightNow. So Idea Lab is not the correct place to ask the queries.
Your query is related to reporting, kindly re-post your query under suitable discussion forum so that your post is visible to bigger section of RightNow experts and they can resolve your queries.
It depends on which object you want to be the parent and which you want to be the child.
To build the relationship create a field in the CO called something like contact_id as an integer. Then go to the relationship tab and build the relationship between the contact and the object using the field you created as one of the keys with the contact.c_id as the other key.