I'm not sure from your OP that you know how scripts are used by FPSC, so I'll try to explain.
Every active, dynamic entity within an FPSC game 'reads' the script nominated within its "Main Script" property one, for each 'frame' of the main game loop. For info, the main game loop is part of the game code that updates all the object posisions, determines object impacts, etc. and is executed many times a second. When people talk of games achieving 60 FPS, they mean that the main game loop is executes 60 times every second.
When it comes to the STATE within a script, I always think of it as a variable. More specifically a variable that only the entity running the script can see. FPSC then provides 1 script CONDITION (to test/question the state variable) and 2 script ACTIONS (to modify the state variable) for you to interact with this state variable.
The state 'variable' of every script starts of at 0. This is why some scripts use the script CONDITION "state=0" during the first few lines to define HUDs and custom variables.
In order to change the value of the state variable, "incstate=x" can be used to increase the state variable by x (incstate=5 would increase the state variable by 5) or "state=x" can used to set the state variable to x.
I hope this helps.