OK, Hector

to set up an advertising account on Facebook, scroll to the bottom of the Facebook home page and click on "advertising", then on the next page click on "Create an advert".
You can decide if you want people to be directed to your facebook page, or to your website (by changing the 'Destination'). As you write the ad, you can see a real time image of it so you know what it's going to look like.
As for targeting it, I've done my mine for my hometown + 16kms, people aged 21+ - this gives me a target audience of 7,360 people.
You can narrow it down to people with certain interests, relationship statuses, education level, and languages spoken - but I've left all that blank to include everyone.
Then you need to specify a budget, and a PPC bid (How much you are willing to pay everytime someone clicks your ad - although they will suggest a figure). I set mine to £6 a day, and only ever top up £40 at a time - and it's currently set at £1.39 per click. If 5000 see your ad, but no-one clicks, you pay nothing.
To be honest, it's straightforward to set up, but not particularly effective. I find the other way of doing it that I mentioned on the other thread gets much better results (and is completely FOC).