Attaching the Firefly

I consider the Firefly's levered attachment mechanism a marvel of mechanical engineering, but it took a while to find a way to engage it without assistance.  Here are my steps, which use the front and rear brakes simultaneously to hold the wheelchair front up without needing to constantly push.  This makes it easier to flip the attachment levers.

1. Roll up to the Firefly, which is standing upright in a corner with its parking brake set.
2. Grab the handlebar and release the parking brake.
3. Roll the Firefly back towards the chair while centering the attachment hooks on the pins. 
4. When the hooks are well-centered, which takes some experience, engage rear wheel locks.
5. Push handlebar forward all the way to lift front casters into the air* and further engage the hooks.
6. Squeeze the Firefly brake.  If the brakes are tight enough, the wheelchair and Firefly will hold the raised-front position, even if you stop pushing the bars.  If the front of the wheelchair doesn't stay up, tighten the front or rear brakes, or inflate rear tires.
7. With the right hand squeezing the front brake, use the left hand to flip the left attachment lever forward.
8. Set the parking brake, switch hands, and flip the right attachment lever.
9. Release the brakes and push the handlebar forward to make the attachment pins seat all the way into the hooks.

*Sometimes, the wheelchair front does not lift very far in Step 5, and I have to recenter the the front wheel/hooks and try again.

These steps apply to the 4-pin attachment mechanism (two on each side of the wheelchair).  They can be adapted to a Firefly without parking brake.