You will need a 7/16 inch wrench to mount the seat to the base.
Remove the four bolts and lock washers from the threaded inserts in the base (2).
Rotate the swivel bearing as shown (4). This will provide clearance to insert the bolts through the slots into the threaded insert in the base.
With the swivel bearing facing down, gently set the seat on top of the base and position the slots in the bottom swivel plate over the threaded inserts (5). You must make sure the swivel plates are in the position shown in #4 above, so you will have room to insert the bolts. IMPORTANT: Be sure to use the lock washer provided for each bolt. Insert and loosely thread each bolt into the threaded inserts so that it is loose enough to let you position and insert all four bolts (6). After all four bolts have been started, continue threading them all the way in and tighten them securely with a 7/16 inch wrench (7). Caution: Do not over-tighten bolts.
Double-check and confirm all four bolts are tight.
Now you're ready for Fun!