Can somebody teach me flowcharts from information technology? I have bought a book but it is shit for understanding.
Essentially 'stages' that have arrows going to and from them. 
Yeah, that's pretty much all there is to it. I imagine your school will say you have to use different shaped boxes and arrows to mean different things, but as far as I recall there's not really any standard - so long as it's easy to read, and the meanings are fairly obvious, you can draw it however you like.
As for structure, something like this:
[Read File]>>>[parse each line into a string]>>>[search strings to find string X]>>>(X found?)>>YES>>[Write X to file]>>>[END]
^ \/
^ NO
^ \/
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
What can I say, I'm bored.
