The Group dashboard, offers the easiest method for creating content types, and linking them to a Group. The Group dashboard replaces the User Dashboard, (found in the upper left-hand part of your screen), only if you are on a page to a Group you have joined. If you cannot find the Group dashboard, you are not on a Group Page or you have not joined that Group.
To create group content, click the button applicable, and the correct Create form will open, automatically placing the correct Group into the Group audience field. To post to additional groups, you will need to go to the bottom of the Create form, and in the Group audience field, next to the Group already placed there, add any additional group(s) you wish to the Autocomplete box, separating each group with a comma.
Adding and linking content, when not beginning on a group page, is almost as easy. It just takes the additional step of manually linking to the correct group, in the Group audience field. As mentioned above, this is all done automatically, if you start on the correct group page, and if your Group audience is only that one group, but either method is acceptable.