Copy the URL from the first page of this thread.

Start a new thread.
Write --- This is a link to my old thread
Paste the link into the new thread

Write whatever else you want
Post that thread

Then copy the URL of that thread.
Come back here and paste the thread on the last post of this thread.
Hit the notify button and ask the moderator to lock your thread for length.

Anything not clear?
Hope that helps.