There are many ways to get people to reply to your posts. Including player names, addition of *****ASTERISKS****, exclamation points, and other symbols often draws attention. Typing WHIR (will help in return) in the title will also get other people to respond, as you have now offered to help them with their issue to the best of your ability. Just make sure you follow through with it or some people may take note and not bother helping in the future.
As far as leaving a link
1) go to the page of the post you plan to attach
2) right click and copy the info in the address bar
3) make your post. When composing your message, right click and paste at the bottom of your post. Hit preview to make sure the link shows and then submit your message.
hope this helps