"Also I know I have to hook up the positive and negative wires correctly on each side, but does it matter which side of the subwoofer I connect them to?"
If you have two sets of terminals on your sub it won't matter which set you hook up to as long as phase is correct. This means the mains must be hooked up correctly also. Yes you can hook up the smaller amp. If the driver is very sensitive, say 90db or better, the 200w amp will put out alot of power.
What 1,400 watt amp did you order?
You may want to go to the Partsexpress.com forum. There's alot of people with years of building their own subs there who are friendly and helpful. It's not real complicated and a very good sub can be built for under 500 bucks.
If the 900 watts you're referring to is what the manufacturer states your bass driver is rated at then you need to know something: That rating is pretty meaningless. I won't go into why here, sorry. There's alot more to a driver than a power rating.
Putting a driver in a box is not as easy as it may appear, at least if you want good performance. If you want good bass a little knowledge will go a long way. For the money you have invested I think you could have done better. Please don't think I'm criticizing what you've done. I'm only trying to help you. I can assure you I would have saved more money if I knew how to listen to others better
A subwoofer shouldn't call attention to itself on music and only a little at most on movies. Many people think that they need to turn ithe sub up to hear it and where it the low bass sound is coming from. This is WRONG and means the bass is overly loud or some other problems exist in your system. A sub should integrate within the system with a nice balanced blend. If the sub sticks out something is wrong.
Forthe money I guesstimate you spent you could have built a box, bought a good driver and a fair sub amp all from Partsexpress or Madisound. I'm assuming you want the best performance you can get for your money. Designing a sub isn't very hard but it isn't that simple either.
At minimum you'll save time and
money going to one of the forums I mentioned above. I believe there are some people on this board that may also be willing to help you design a sub. Try posting in the Lab area as we don't have a speaker building forum.
Both Partsexpress and Madisound with give you parameters for an enclosure if you buy the driver from them btw. If you would like personal help you can PM me. Cheers