SI derived units: Another name for the Volt
a Volt is a Joule per Coulomb.  so each Coulomb of charge has V Joules of energy packed in them somehow.  

an Ampere is a Coulomb per second.  so in one second, I coulombs of charge pass by.

so if I coulombs of charge pass by a boundary, each packing V Joules of energy, that means VI joules of energy are being transferred (or used) each second.  that is the rate of energy usage or "power".

so a Watt is one Joule per Second.  if VI joules of energy are transferred each second, that's a power of VI watts.

an Ohm is a Volt per Ampere.  for each ampere of current stuffed into R ohms of resistance, will result in R volts.  so for I amperes of current stuffed into R ohms, the resulting voltage across the resistances will be IR volts.