ok so terrain has 2 types, Defensive, and Dangerous. during setup the scenario chosen will determine how many of each type you use. randomly draw cards for each type (each card has one of each)
once you collide with terrain you have to deal with its effects and then you have the option to enter it (if it has a capacity)
terrain effects are
Cover- increase defense vs ranged attacks while occupying.
Deadly- suffer wounds when colliding.
Elevated- ignore other units and terrain when measuring LOS
Fortified- increase defense vs melee attacks while occupying.
Exposed- this terrain is ignored for LOS
Taxing- take panic when colliding.
when you occupy terrain there is a limit to how many trays you have limited by the capacity of the terrain. this is neat because when you make terrain you can say this terrain holds X trays then make sure there is that room on the terrain piece. you can make a terrain piece that cant fit any trays and no game piece will ever be able to enter it.
also when occupying terrain your facing doesnt matter, you have 360 LOS and if someone charges the terrain they also count as charging you.