It just checks to see if the text you specify is at the coordinates x, y. Most of the parameters are pretty self-explanatory, and if you look at the description in the guide you should figure out what they do. If you have specific questions, just ask.
In order to use the F2 you would use the funtion "IsFKeyDown(num:byte)", which returns a boolean depending on whether the key you specify is down at the time. The 'num' argument cooresponds to the number of the F key, so F2 would be 2.
In order to have scar do something if the key is down, you just throw it in a conditional.
SCAR Code:
if (IsFKeyDown(2)) then
//whatever you want it to do
This will only check once if the key is down however, so you need to put it in a loop
SCAR Code:
repeat
if (IsFKeyDown(2)) then
GetTexAtEx(.....);
until (false)
P.S: Bumping is unnecessary on this forum, so don't do it.