Want to get subs installed in truck, don't understand anything about it

So, let me apologize ahead of time for my complete ignorance on this subject, I know nothing about it (which is why I'm coming here).

I want to get 2 10" or 2 12" subs installed in my 2005 extended cab Ford f150. My problem is, I don't understand all the technical mumbo-jumbo that is associated with purchasing subs and amps etc. I was wondering if anyone could explain these numbers to me and point me in the direction of an amp that can power 2 of the following subs, since I do not trust any of the car audio installation places around my hometown to be honest with me and not just attempt to shove product at me:

(These are the specs for 1 sub, I want 2 if possible)

Kicker CVR124 12" Dual 4 ohm CompVR Series Car Subwoofer

Peak Power: 800 Watts
RMS Power: 400 Watts
Impedance: Dual4 Ohm
Sensitivity: 86.9 dB 1w/1m
Frequency Response: 25-500 Hz
Mounting Depth: 6-1/4"
Mounting Cutout: 11"
Recommend Sealed Box Volume: 1.00 - 4.60 Cubic Feet
Recommend Vented Box Volume: 1.75 - 2.25 Cubic Feet

The first thing you should probably account for is enclosure space. Are you planning on putting them under the seat?
There's only one design I know of for two 12's in an ext cab F150 and it's around 0.65 cf per sub. The CVR's recommend 1.0 minimum.
They'll WORK in a smaller box, but the sound quality is likely to suffer. You might be able to improve the sound a little by adding some polyfill.
Alternatively - a pair of 10's might sound better and be nearly as loud. Or a single 12 may be an option also.

As for clarification on the numbers…
Peak power -- Meaningless, ignore it.
RMS power -- the power rating that matters.
Impedance - also important. Big factor in choosing an amp. One dual 4 ohm sub can be operated at 2 or 8 ohms. A pair can be wired together for 1 or 4 ohms. Since these are 400w rms subs (800w rms total) a good amp option for a pair of them would be a mono amp that's around 800w rms at 1 ohm (you might broaden your search to 1000w rms giving you a lot more choices).

Sensitivity - A measure of the speaker's efficiency -- not a huge concern for most people.
Freq response -- most 12's will have roughly the same capability - and a few hz won't make a difference you can hear anyway.
Mounting depth -- will definitely be an issue if you're mounting under the seat. Actually, I'm about certain these 12's won't fit in any box that will fit under the seat -- you may be limited to shallow mount subs.
Cutout - self explanatory

Sealed box volume: hopefully this is self explanatory as well
Vented/Ported box volume: ^^