Now we will want to join the Bed frame with the Cage frame. Drill a hole through the center of the rounded ends of your Bed frame, large enough to accomodate the lag bolts you have. Measure and drill corresponding holes on the "feet" of the Cage frame. Make sure to measure for a 1/4" gap between the Cage frame legs and the Bed frame legs. Use your 1" hole saw to make countersink holes, so that the lag bolt head will sit flush. Use your lag bolts to join the two frames. Don't over tighten the bolts, we want to allow some movement.
With this, youre basic frame should be complete and fit together nicely.