bluetooth is like a wave, used to send and receive files i.e images, sound etc via your hand phone and also computer.
what you need to do is go to your phone's menu and usually a bluetooth section is in the connection menu. there, make sure you switch ON the Bluetooth before you want to receive anything. you can also personalized your phone by changing the name of the phone.once the bluetooth is on, you can receive files from anybody. if you want to send a file to another phone, just make sure the person switch on the phone and before sending the file, your phone will automatically search the bluetooth connection available.
a bluetooth connection can be traced withing the range of 10 metres (depends on the brand of your phone) and it cannot be blocked by anything e.g. a wall, as it will cut the connection