Same sex postal vote

There's been a lot of comment and debate about the impending postal vote for same sex marriage.
I won't go into that.
However, an interesting comment I heard from a commentator was that they may need to provide explicit details on how to return the vote ie. How to post the vote back.
Many of today's youth have never posted a letter in their life.
So they will need to be told to:

• Mark the voting paper and place in the envelope
• Lick the back of the envelope and seal it
• Take the letter to a Post Office or find a red box on the street and insert in the box (before 6pm)

Actually, the best way to get the message across is via a video demonstrating how to post a letter on YouTube.