Reply: Phantom power can be supplied either by a stand-alone supply or by a mixer that has phantom power built in. Some supplies have one input connector for one microphone; others have two for two microphones, and so on.
Take a close look at your mixer to find out the manufacturer and model number. You can look up its specs online (or look for its manual) and see if the mixer supplies phantom power. If it does, you don't need any external phantom power supplies. Just connect the mics to the mixer, and the mixer will supply phantom power for the mics.
Check the data sheet for each Crown mic model you want to use. The spec "Operating Voltage" tells how many volts of phantom power the mic requires, such as 12 to 48 volts. Make sure your mixer supplies the required voltage.
An explanation of phantom power is in the link below. Once there, scroll down.
Here is a link to information on miking a conference:
Teleconferencing and Distance Learning Application Guide.