The online help file outlines exactly what is the difference between environmental, static, and total in context of Flow Sim, have a read through it. I usually set inputs as static and outputs as environmental. Analysis time is not something you should mess with unless your simulation is extremely unstable and you want a finer temporal resolution (lowering your time step will come at the cost of computational time.)
there are a bunch of videos on youtube and discussions about this on the internet, I think someone actually asked this just recently.
in flow your 2 options are to set a pressure difference and find out the flow rate or set a flow rate and a pressure and find the pressure on the flow end.
I would recommend thinking about how you will test this in the physical world and then set it up the same way based on information that you have.