TripleAAA - I'll explain:
I installed cable modems for the past four years (been there, done that).
Your house is new, which means that it should be pre-wired for cable. Meaning, you probably will have cable jacks/plates on walls scattered throughout the house. Behind these jacks, the coaxial cable is ran through your walls and they ALL will end up at a common starting point. About 95% of the time, this "junction" of cables is located in a utility room where your fuse box, furnace, etc is. If you have a basement, it will be in an unfinished part of that. You'll see a bunch of black cable hanging out somewhere.
When a cable guy comes to turn cable on for the first time, he'll run you a cable line (called the drop) from the cable system interface point in your yard (usually a light-green box somewhere) or above the street (if you have aerial utilities in that area), to your house. The entry-point should be right near where all of those cables meet within the house. Some new houses have a pre-fed line that goes outside and is sitting there waiting to be tapped into. What I mean is... say you have 10 cables sitting there. 9 will be cable outlets throughout your house, and 1 will be a line that goes outside (right on the other side of that wall) and the cable guy uses this to splice into instead of drilling a hole and running his own line in.
Either way, you're going to end up with a "hot" line sitting right there by all of your other cables. Hot meaning that one of them is from outside, and is directly from the main cable lines... and you just have to screw it into a tv to get a picture. But of course you're not going to have a tv sitting right there in your utility room. So what you have to do is "split" the signal in that hot line to feed all of the cable outlets in your house. This is done with a little device called a splitter. A splitter has various amounts of ports on it. You will screw the the hot, active line from outside into the only port labeled "in". You will be left with X amount of ports that are all labeled "out". You screw the desired cables lines (the ones that all meet up right there, from throughout the house) into these "out" ports. Doing so splices those cable jacks into the active line, and they'll now be "hot."
What a cable company will do to get as much money out of people, is to act like "activating" each outlet is a big deal, and will charge a per/outlet activation fee. Yes, if you're understanding this correctly, this "activation" is simply screwing a cable line into an "out" port on that splitter. That's it. That's a one-time activation charge, and after that you'll just get a normal cable bill. When I worked, each activation cost about $12 for the customer.
If you get a contractor on the job, they usually get paid per "thing" they do at the site. A standard, well-paying thing for them is to activate each outlet. They'll try to sell you on just getting them all turned on so you don't have to deal with it in the future. Well, you'll be armed with knowledge now and will know that activating outlets is a ripoff and easy to do. ... *unless*... those cable ends don't have the fitting on them (the metal part that allows the screw-in mechanism). That is a pain to do by yourself. You need specific tools, and if you don't know what you're doing... you can easily make a faulty fitting, resulting in a snowy, crappy picture on that cable line.
Here's what I suggest doing if you want to activate all of your outlets. Just tell whoever comes out that you want one outlet activated (probably your main tv). If you don't have fittings on your cable ends (at both the end at the cable jack on the wall, and at the other end of the cable at that common junction point downstairs), you might be able to get the cable guy to do it for you while he's there. Just slip him a $10 or something. If you already have those cable ends, then you're good to go. Just tell him to hook up one outlet, and get him out of there.
If that's the case, you're going to go downstairs and take a look. What you'll see is that the "hot" cable line from outside is connected to the one cable line that has the newly activated TV (whichever one you told the cable guy to turn on). All of the other cables will be hanging there still, not connected to anything. To activate all of these outlets yourself, you just need to add that splitter into the mess. You can buy a splitter (they usually come with 2, 3, 4, and 9 ports) at many stores. General rule: the heavier the splitter, the more solid and dependable it is. Just unscrew the hot line from the lone tv line, and screw that into the in-port. All of the others go into the out-ports. There you go.
Phew - long winded, I know. Was trying to be thorough though. Let me know if something is unclear.