How you make topics stick?

and how do i lock them?

I assume you are talking about the Bravenet forum service. This is from the Message Forum service FAQ.

38. How do I lock or sticky a thread in my Message Forum?

a) Login to your Bravenet account and click on "Message Forum" in your list of Registered Services

b) Click on "Delete Messages"

c) Click the message you would like to lock or sticky

d) Click on the "Lock This Thread" or "Sticky this Post" link.

Locking a thread will prevent new replies.

Stickied posts will appear at the top of Message Forum posts.