Now that you have procured a tie, set it aside. Prep yourself by moving your collar to the upright position and fastening your seatbelt has we prepare for takeoff.
Make your tie so there is a thinner side to your right and the fatter side on your left. Have the thinner side about 1/4th the length of the fatter side.
Cross the fat side right in front of the skinny side.
Tug the short, thin down a bit as you pass the long, fat piece behind it. The two pieces should be where they started, with the short, thin piece on your right/middle and the long piece on the left.
While still applying liberal pressure downward on the short, thin piece, pass the long, fat piece in front of it. The long piece should be on top.
Another pass... The two pieces should again be in their original positions, the short, thin piece on the right/middle and the long, fat piece on the left.
Pass again. The fat piece is on top of the thin piece, and on your right. Tug outward on the noose you've created and pull the long, fat piece upward from under, it should rub your neck as you pull.
If you got through that, the worst is over. You should have the long, fat piece covering the knots you've made as well as the short, thin piece.
Now loosen the short, thin piece at the knot and slide the long, fat piece through. Depending on how much you loosen it, this might cause your tie to be too long. Restart and adjust accordingly.
You are done. Tighten the tie by taking hold of the knot near your neck and pulling it up while simultaneously tugging the short, thin piece (hidden by the fat piece) downward.
Looking good! Change the length of the tie: Go back to the beginning and adjust the short, thin side's length. A long short side will make the long, fat side short. Find the ratio that works for you.