i understant it. However i don't really get how it work in fact
Seems to me that means you didn't understand it.
EEPROM is a storage area which retains its values when the Arduino is powered off or reset. Your sketch can write values to the EEPROM and read them back. That's all it does.
If you want to be able to read/write to the EEPROM from a computer, you'd need to write a sketch that received commands from the computer, did whatever read/write operation was defined in the command and then sent back any response you needed. There is a whole section of the forum focusing on ways to communicate between a PC and your Arduino, and that part of the problem has nothing to do with the EEPROM.