ts really quite simple:
Tesla makes a basic ~10 kW charger. It takes AC from the grid an converts it to DC at the right voltage and current that your battery can handle, adjusting the voltage and current based on the power available from the grid, your state of charge, battery temperature, and other factors. One can connect these chargers together to provide more power depending on how many you want to buy and how much power you want to pay the power company to provide you with.
Each Tesla comes with one charger in it to allow you to charge at up to ~10 kW DC. It can draw between 120 and 240 volts from the grid at from 12 to 40 amps depending on what your wiring and grid connection can provide. You can optionally buy another charger to put in your car allowing it to charge up to ~20 kW DC if your house can provide up to 80 amps and 240 volts.
A Tesla Supercharger is 12 of these 10 kW chargers, all tied together to provide up to 120 kW of DC. It, of course requires a ~480 volt, ~250 amp connection from the grid, something no normal house would have available and you'd have to buy 11 more chargers. Tesla generously provides those stacks of 12 chargers in public places, calling them Superchargers, where their customers can share them to get fast charging without having to buy anything else for their cars.
Its really a great thing!