Hi Annelouise
Do you mean the weight loss tickers that some people have in their signature? If so, firstly you need to wait 20 days after joining and secondly have made at least 20 posts before your signature option is made available to you (I'm eagerly waiting for my 20 days to be up, I seem to have made the post count easy enough
).
So, once your signature option is available, if you then go to the forum index and select 'Announcements and Forum Help', there's a sticky thread on there about how to set your tracker up.
Good luck with seeing those pounds disappear!