Add up the "amps" each thing you want to hook up draws. Fans usually have this written on them. For lamps, you can find the current (amps) by dividing the power rating (watts) by the voltage (12V, in this case).
You can't go over the rating of your power supply - apparently 2A. As long as you're under, you're just fine.
Note that some things may be rated in milliamps (mA). 1000mA is equal to 1A.