Sorry, some of your questions are not clear to us.
Anyway:
You need a 12VAC power supply to power the VM201. A 12VDC power supply is not suited.
The power supply needs to be able to supply at least 500mA.
You can switch the AC power with the VM201, but make sure all wiring is done according to good engineering practice.
If you have a doubt, consult a professional. Make sure to use a suitable enclosure, e.g. part # B8006
If you use the ‘pulse’-option, the output will stay on for a pre-set time. When this time elapses, the output will turn off.