"I want to create a link for one post only."
Find the number of the post that you want to post the URL link to (lower left hand side of the post), right click, then choose "copy link address", or the closest text to that (may be different on different browsers).
Paste the copied link into your own post.
Thanks for helping me out, Bik. I understand how to do it now.
BTW, I’m a Pure Blood too.