The easiest way of attaching a swing to a wooden beam is by means of the Swing Hook LS.
The hook has a screw thread with which you can twist the hook into the beam - these are sold singly
The Swing Hook BT is a swing hook, which can be inserted through a wooden beam and then fixed in place by fastening the nuts
This swing hook is particularly useful if you already have a swing with holes all through the top beam - these are sold singly