First of all, go to "View"
"Building info" in the menu. Now some information about the building is shown in the property grid, you may change the name of the building or the scale as well. The scale is the pixel-to-meter factor, you may enter a value by hand here or do the following:
Go to "Building"
"Calibrate Scale", a dialog box is opened. Now zoom into your map to find an imaginary line in the building you know the length of. Click on one point of this line, drag the created line to the endpoint of your imaginary line and click there again. Now enter the length in meters into the input field in the dialog box and press "OK". The program now calculates an appropriate scale.
Quite interesting might be the "Interpolator" subbox. Here you can change the interpolation color, method and parameters. See the extra documentation about the interpolator parameters for details.
If you have changed the color of the interpolation, you might be unsure which color stands for what. To help you, a legend is integrated in the program, just choose "View"
"Show Legend" in the menu.
If you click on the floor map, you will see the floor properties on the right side. Change what you want. You are also able to hide the interpolation to view only the map of the floor. If you click a measuring point on the map, the property grid will show you the measured quality (yes, you can change it) with the measuring date and an additional note.