Mercury In Aquarius?

Ok, in my reading by Huredriel , it suggested that the person I am looking at or for has mercury in aquarius. I'm not that up on my astrology. I know that's one of the planets in one of the houses and I looked up the description of that sort of person online.
It said:
MERCURY IN AQUARIUS
Independent minded, these people do not like being told what to think. They need the freedom to find their own intellectual interests and they frequently hold radical views. They like issues to be clear cut.

It sounds good, I really think I'd like someone like that...
BUT>>>
I don't know how one does someone's chart to that extent. My undertanding of finding someone's sign extends to their sun sign and their rising sign and that's about it.
Can someone please enlighten me?

Firstly, to get someone's Mercury sign, you need to find out their birthday and look up the Mercury placement in an ephemeris. There's a great one over at http://www.astro.com - just click on the right year and find the correct date.

Also, to gain a real understanding of compatibility through someone's natal chart, you need to look not simply at the signs and houses, but also the aspects between the planets. I would suggest looking at more than just sun/ASC/mercury, but at least sun, moon, mercury, venus, mars, jupiter, saturn and ASC. There are many, many, many people w/Mercury in Aquarius. There is no way you could be compatible w/them all. You need to look at the whole chart.