I do not understand how to tell the power an amp can give to

I do not understand how to tell the power an amp can give to my subwoofers.?
I really don’t have clue how to know how much power I can run my subwoofers at. I have not bought an amp or subs but im thinking to running them anywhere from 400w 800w. I don't know any amps I could get or how to tell if the amp can rund two subwoofers that will each be running at watts.

you may want to match the RMS power ranking of the speakers to the RMS power ranking of the amp. If you want two 400w RMS speakers, you will need an amp rated at 800w RMS. you will also have to match the impendence ohm ranking of your speakers to what the amp is able of handling. If your amp is stable at 2ohms and you will be running it linked, you will need speakers that may be wired to present a four ohm load to the amp. like two 8ohm speakers or a pair of dual voice coil speakers that have four ohm voice coils.

woofersetc.com
What you want is allready have inside
You just use your bit power to click inside.dont be lazy.
Ha.ha.