Either way, use a high power eyepiece. Focus on a bright star. Then turn the focus knob till it's way out of focuc. You should see a donut shape. The black center of the donut should be right in the center. Check both directions. First turn the focus knobe one way, then check the other way. If the black circle is in the center of the donut in both directions, your OK. If it's off center, you need to collimate. For a reflector there should be screws to adjust on the bottom of the scope. They will move the primary mirror. Keep adjusting till you get the black circle in the center as best you can. It's better to get a laser collimator of some type, it will be more accurate. For an SCT, there are screws on the back of the secondary mirror. Do the same thing, Turn the screws till you can get the black circle in the middle of the donut. These screws should need very little adjusting. A quarter of a turn should be dramatic. If you can't get it your self, you can send it back to Celestron, they'll do it and check if anything else might be wrong.
That's it;
BOB SAL