In reply to Pursued by a bear:
Agree with the advice to check online for guides. There are loads which are useful.
I use an air blower first(the one you squeeze not the one in a can with propellant).
It is sometime said that all a blower does is move the dust around in the camera. That might be true but if a speck of dust lodges somewhere else in the camera it is unlikely to do any damage(we are talking about VERY small specks not great chunks of visible muck) and it cannot show up on the image.
If that does not work then I used a wet cleaning kit. Get one the right size for the size of your sensor.
Before you do a clean with a solution make sure the camera battery is fully charged. It is unlikely to happen but if the the battery loses charge during the cleaning process the mirror can, perhaps will, flip back down, which you don't want to happen.
The instructions with cleaning kit are good. Just follow them and online video guidance and you'll be OK. It is easier and much less scary than it first seems.
You might find you need to clean the sensor a second time to remove all the spots.
Dave