Starting from the top circle, the C70, C71, C72, C73 are the names of the individual circuits. The next line down with the 10, 14, and 16 are the gauge thickness of wire that is being used in that circuit, and the bottom line DB/YL, DB/VT, DB/OR, DB/BR are the colors of the wires. (Dark Blue/Yellow, Dark Blue/Violet, Dark Blue/Orange, Dark Blue/Brown).
Not sure if the S3224 was included, but ill touch on it anyways. The black dot labeled S3224 is a splice, meaning two wires are basically tied or soldered together.
Moving down, C200 is the name of a connector plug along the circuit. If you download the factory service manual you can look up the connector, what it looks like, and what each pin goes to. The two upward arrows with a small 1, 5, 6, and 3 are the corresponding slot that the wire plugs into in the connector. (The factory service manual, which can be downloaded in pdf form somewhere on this forum has pictures and pinouts of all the connectors in the truck. It is incredibly useful.)
Moving down to the arrows at the AC Controller labeled C2. Those are the second connector on the AC control unit and again the wires are numbered based on the slot in the connector. The service manual will have a picture of the C2 AC controller connector so you know which connector is which.
The 1, 2, 3, 4, 5 inside the box are the different settings for the blower motor. Off, low, medium 1, medium 2, and high. The part that looks like the arm of a clock is the knob that you turn to select the setting.
Hope that helps you and others along the way!