To insert a light fixture, go to
DM Electrical 
Light Fixtures Insert Light Fixture
You will be taken to the Insert Light Fixture dialog box as appears below.
Make certain light fixture B is selected as shown above, then press OK.
Specify the insertion point and rotation angle of the light fixture. After inserting the fixture, you will be prompted to insert more fixtures of the same type. When you are done inserting fixtures, press ENTER to end the command.
Insert two B light fixtures in Offices 103, 105, and 107 and eight B light fixtures in Conference 102 to match the drawing shown below. The light fixtures can be inserted using the Insert Light Fixture command or copied using the AutoCAD copy command. Light fixtures can be moved and erased using the standard AutoCAD move and erase commands.
Using the method described above, place eight S fixtures around the outside of the building as shown in the drawing below.
Now that you have light fixtures inserted on the drawing, you may want to also insert a light fixture callout.