The real benefit of using federations is that you can bring multiple models together regardless of their file formats. You can have as many federations in your project as you like. New model revisions will automatically update in federations so that you are always looking at the latest information.
Here is how you can create one in any of your projects:
Open the project tab and navigate over to the + box
Hover over the right side of the box
Click on the greyed-out option where it says Federation
A new federation window will pop up where you will be required to provide the following information:
Federation name (127 Character Limit)
Select the models you want in your federation
(Box next to the Available will select/deselect all of the models)
Press the Save button
The new federation will appear in the list of models. You can easily identify it since all of the federations are in blue containers.
Edit a Federation
Should you find the need to edit an existing federation, simply click on the edit button and remove or add any of the models you wish.