In WordPress, when you first set it up, your urls when you post look something like this: http://www.chrisrat.com/blog/?p=123. Not entirely the most descriptive! I have to thank my friends over at BrainPOP UK for the tip here to turn that into a descriptive URL.
This is a short post, as it is super easy to sort. In your WordPress control panel, go to ‘Settings’ then to ‘Permalinks’ and you will see something like this: