I want to add a new BO to the project how can I do this?

 You need to add a a new business object from within the VS solution. right click on the project\add new item. Select a stratframe business object. Name it. Now go to the BOM and the bus obj should be there with a red x indicating that it has not been mapped. click configure and select the table. then build partial or build all. Once this is done rebuild the solution in VS if you are using a separate Bo project so the other projects will be able to "see" it.

Paul is exactly right.  Business objects are not created through the BO Mapper, just mapped to the schema and build the partial classes.  If you need some more explanation as to how to add a business object to a project you are welcome to post here again...but I recommend looking at the tutorial in the documentation.  It takes you step by step in creating a BO and binding it to controls.