To create a new floor

Click the New icon.
The Add floor tool settings window opens.
Do one of the following:

Enter the path to the floor plan document you want to reference in the File name text field.

or
Click the browse button to open the Select floor dialog box. Set the File of type filter to Design files (*.dgn), and browse the disk to the floor plan file you want to reference. Click Open.
The DGN file may contain multiple models. You must select the DGN model to reference from the Model drop-down list.
Enter a name for the new floor in the Floor name text field.
Enter an elevation for the new floor in the available Level setting. For instance, if the new floor is a ground floor located directly on the ground, enter zero.
Click OK.
The floor plan DGN model is referenced into your project. The new floor is added to the OpenBuildings Energy Simulator Project Tree using the name you just entered; Floor: [your name]