Simple explanation for static and dynamic pressure?
Static pressure is a force per unit of area due to fluid molecular motion leading to some statistical collisions with its environment (a solid submerged or another fluid for instance). Pressure gives an information of the fluid state (in a thermodynamics sense) and is a « measure » of the force apply by molecules as a whole. Wikipedia could be helpful on that topic.
Dynamic pressure is a bit confusing term as it is the kinetic energy of a fluid parcel (a unit of volume). This parcel has different form of energy (internal, pressure, potential) and this one is energy due to its motion. But it is not a pressure at all and does not act on the solid. However, disturbance created by the body (the flat plate on the picture) will slow down the flow in front, increasing pressure near surfaces. But this is still that pressure difference between front and back which is « felt » by the plate.
In fact, I believe this is the reason why we call it dynamic pressure. It is an energy form (known as kinetic energy) which is easily changed into pressure (or inversely pressure changing to kinetic energy) during fluid dynamics process: drag and lift are created like this on a flow around a body, gas expanding inside jet engine nozzle for thrust generation, etc..