Many Quickie wheelchairs will have almost identical instructions - but keep in mind each wheelchair user's needs are unique and they use their chairs differently.
Ideally, it is easiest to mount when a wheelchair is not occupied.
Optional:

For this wheelchair we know we will have to clamp to the round tubing.
Determine the mounting side for best access. (consider the users dominant hand and reach)
In this example:
The seat cushion has been removed for clarity
We decide to mount on the right side of the chair.
Before we begin mounting, please consider anything that might obstruct the wheelchair bracket and post.
Common things to consider:
Here we try and clamp the seat-tubing directly under the cushion
Unfortunately - you can see here that with a post inserted, the brake lever cannot fully function
We now attempt to clamp to the upright footrest receiver.
Notice how the wheelchair brakes are already in its "down" position - and does not obstruct the lever movement.
Checking to ensure that foot-rest swing-away is possible in this configuration.
Since we decided to use the WC-LAE,
LOOSELY attach the WC-LAE to the
Wheelchair Clamp for 1" Round Tube (WC-R1)
like shown in this picture.
Using the 3/16" Hex Key, tighten both bolts down.
At this point, you can tighten these bolts down to full torque

The WC-LAE are packaged with four screws and two locking nuts.
Attach the Solid Wheelchair Bracket using the two longer screws and the two locking nuts.