how send the leter to your friends?

first find a piece of paper

second find a pen

third write sth on the paper

fourth find an envelope and put stamps on it.

fifth put the paper into the envelope

sixth seal the envelope

seventh give your friend a call to let him pick the the envelope up.

How to send the letter to your friends?怎样发送那封信给你的朋友?

The sender's name and address put it one the top left corner.
The Receiver's name and address put it on the center of the envelope.
the last put a stamp on the top right corner!
then dive the letter to post office!

what's the mean?