The first twenty seconds of this video shows Master Bob Boyd doing the first move and giving invaluable foundational knowledge in the narrative. This is available on you tube on the IpTaiChi channel:
The first move, two hands begin tai chi, actually consists of four distinct parts, each with a particular focus and intent.
Consider:
The first move introduces the first front stance and sets the stage for understanding proper footwork, crossing the center line, and moving from a unified core.
Martial Applications
In tai chi, the martial concept is to unbalance your opponent so that the opportunity is yours. For the beginner, it is not important to follow the martial ideas, but it is important to know that they exist.
Each move has a number of possible applications.
The first part of the move uproots the opponent up.
The second part of the move is like the first, yet it is its inverse; designed to break the body balance in a downward direction.
The third part of the move could be to unbalance the opponent to the side.
So you can see, perhaps, that you can move your opponent up, down, left, right, forward or back depending on your intent.
Of course, these ideas follow will follow the movement of your core.
If you are into the idea of the martial art, at this stage, be very careful not to force anything. Tai chi uses physics in subtle ways that are developed over time. If you feel tension in your body anywhere, work to convert that tension into soft, dynamic, unified action.