Lude Generation

Guys, i am not sure if im being stupid or what
How do you change the title of a thread, E.G build thread. So for example i want to add on the end like "engine in" or "parts fitted". Like Merlin is doing with his . . . So it changes in the new post section.
cheers chaps

Edit the very first post in the thread and change the title there.

Ah ok. Thank you