Translation
I am the noble Posta di Fenestra Destra (Window Guard on the right), and for beating and wounding I am always ready, and I care little against a long spear. Also, with a sword, I could wait for the long spear standing in this guard, which beats aside and obstructs every thrust. And I can exchange the thrust, and beat to the ground without fail. I want to finish in the play that is after this.
Explanation
Posta di Fenestra translates easily across the different weapons of armizare. It is used not only with the spear, but also the sword in one hand, sword in two hands and pollaxe. It can be used equally well on either side of the body.
With the left foot forward and in a rear weighted stance, hold the spear in much the same way as you would a sword. The left hand is at the base of the spear shaft, with the right hand on top. Fiore shows holding the weapon quite a long way down the shaft. The closer your right hand sits to the balance point, the less reach, but more control you have. Your right hand should rest next to your ear.
This posta is ideally suited to exchanging or breaking the thrust. In beating aside incoming attacks, slide the front foot offline and step through with the back. Cut down and across with your arms, but keep the head of the spear as still as possible. This will give you much greater control and balance, as well as leaving you well placed to deliver a counter strike.