Firstly check the measurement from the ceiling to the window both sides to see if the window is fairly square.
If it looks okay measure up between 10 - 15cm and mark with a pencil, the pole should also be anything from 20cm wider than the window opening. For a small pole you will just have 2 brackets which you should put up keeping on your pencil line - the pole you have purchased should give you fitting instructions but if not put each bracket well in from the end of the pole - let's say 20cm approx. One ring should be placed between the bracket and the end of the pole which will anchor the curtain at the sides.
You will need a drill and wrawlplugs with the screws in your pack. If you haven't used one before you might wish to ask an experienced friend for assistance!
Retired fitter, November 2008