Then lay the body and boom on the table and overlap them about 1/4".

Use a straightedge to align the body and boom together. Then cut a small piece of balsawood 7/8" long and use it as a gage for aligning the tail boom. For the model to fly correctly, the tail boom needs to be offset to the side a little to make it turn, and up a little to help it fly correctly.
(Note: the body and boom are actually upside down at this point of the assembly.)

Set the boom up as shown in the photos below.

Now using a pin, apply small drops of glue around the joint to glue the boom to the body.
As an alternate method you can pick the boom up and place a small drop of superglue where the boom was laying, then reposition the boom back onto the body. If you choose this method, then you must position the boom quickly or the superglue may dry before you have it positioned it correctly.

After the glue has dried, the boom should look like this when viewed from above looking back. The boom is intentionally offset like this to help the model circle to the left.

Also notice that the boom now points upwards.