If the master who is in the guard position with the dagger is attacked with the sword by a blow to the head, he passes forward and makes his cover and turns his opponent by pushing on the elbow. And he immediately follows with a strike. Also he can bind the sword arm in the same way as the fourth play of the sword in one hand can do. And also from the third play of the first dagger master you will find that middle bind that is near the face by a hands span.
You are defending yourself against a fendente attack. The basic cover of the 1st master is the common pattern of stepping offline with the front foot, and then sweeping across the body as you step through with your back foot.
In this instance, you need to step forward with your right foot as well as across to the outside line. Holding the blade of the dagger against your forearm, cross the sword at the strong of the blade. This will make your cover much safer and give you far greater control over your opponents weapon.
Lifting your right elbow as high as shown here is mechanically weak and the arm is in danger of collapsing under the blow. Always keep your hand higher than your elbow. Ideally, the forearm should be held at a 45 degree. The attack should be directed to slide down the forearm to the right.
As you make the cover, reach forward to catch your opponents elbow. You will be at the position depicted.
Step through with your left foot. As you do so, push the elbow. This will leave you in a stable position, with a clear line to strike into your opponents neck or the right side of their ribs. Alternatively, you could reach over the sword arm, and stab then in the front.
Fiore also suggests that instead of pushing the elbow as you step through, you could slide your left hand under your opponents forearm and enter a middle bind. This will twist your opponent, leaving a clear line for you to strike down the centre to the face or chest. Examples of this counter can be seen being used by the 4th scholar of the sword in one hand, and the 1st scholar of the 1st master of dagger.