Shellie,
In order to merge two documents in Fortis, one document will need to be out of the Fortis system or located in an Inbasket and another will need to be located in the database.
1. Open a document in the database you wish to add to.
2. Select the Edit drop down and chose Insert Before Page(or Insert After Page).
3. Select where the additional file would be and then select the file in that location.
Note: If you wish to merge two documents in the Database, you will either need to export one out of Fortis or to an InBasket.