I have broken the combination down into the three movements to make it easier to grasp.

Movement 1.
Queixada-Dobrado (a name I just made up then).

Go into the movement as if you were about to kick the queixada. twist the hip, but dont lift the queixada kicking leg just yet.
Sink the weight through the bum and reach with the arm (the arm that is closest to your queixada kicking side). Turn the hip over as you lean and kick through with the opposite leg. (not the queixada kicking leg).
Land like an S-dobrado. It is essentially an S-dobrado from a queixada position. Try and practice landing with the body high, and keeping the second leg that comes around, off the floor at the end of the movement. (will make it easier for you to join it in the combination later on).

Movement 2.
Helicoptor
For the ease of explanation, i am going to refer to the way it is done in this video.
The helicoptor is a movement that I found extremely difficult to learn by myself. Thus I would recommend finding someone who can do it to help you.
Begin by doing an Au then the leg that you would normally land on, in this case, the left leg, will sweep through, low to the ground. The right leg is open, and follows the left.

keep both hands on the floor as long as possible. The movement has three stages, the descent and isolation of the hands going down, the hands staying fixed on the ground and the turning of the legs, and then the third stage is when the Right foot lands on the ground, the legs stay almost neutral whilst the body unwinds itself.

in this third stage, you must push off hard from the ground with the arms, and keep the right leg hard. You must not bend in the hip or you will not be able to push up and out of the movement.

movement 3
backwards walkover, one handed switch

this movement you can begin practicing as if you were practicing an Au. Try and begin facing side on. You could also just practice doing it like a backwards walkover, (if you can do them already), but land on the opposite leg you normally would. You dont need to do it on just one arm, but it does look a little cooler if you do.

tips
Try and do each of the movements individually first, before putting them into the combination.
keep the body rolling, let the motion guide you. Slow it down, no need to rush through it, this will help with the balance.
If you cant do the whole sequence but only parts of it, that is great! use some of those movements to create your own unique combinations!