The difference between total and static pressure is something you will learn when you start taking fluid mechanics courses. Static pressure is just "pressure", it's the mechanical potential of a fluid at a given point. "Total pressure" is similar to stagnation pressure, it's the sum of the potential and kinetic energies of a fluid at a given point. If you haven't had these courses yet then you probably don't need to worry about the details for your project, check with your professor to find out what the scope of the project entails.
Environmental pressure is a concept used for this CFD code. The details of what it means can be found in the online help documentation:
Allows you to specify Static Pressure, Total Pressure or Environment Pressure on the selected faces. The Environment Pressure condition is interpreted by Flow Simulation as a total pressure for inlet flows and as a static pressure for outlet flows. If in the course of calculation a vortex crosses an opening with the Environment pressure condition specified, this pressure is considered as the total pressure for the part of opening through which the flow enters the model and as the static pressure for the part of opening through which the flow leaves the model. Additionally, you can specify fluid temperature (and concentrations for multiple fluids), turbulence parameters and boundary layer parameters. These settings define the fluid entering the model through the opening.
If you explain, explain it properly.
It's the Bernoulli equation: Total pressure = Static pressure + Dynamic Pressure.
If the air is stagnating which means the velocity is zero this is called stagnating pressure.