I have assumed you mean a 'neck tie'
1) place the tie around the neck with the narrow and shortest length to the left (assuming you are right handed otherwise reverse this instruction)
2) Take the long end at the right and pass around the short end bringing it out through the top such that you have a loop.
3)Take the long end completely around the back of the loop and across the front
4) Pass the same end through the knot so formed and tighten to taste.
A much simpler way is to ask your friend to SHOW you . LOL