once you are bc authenticated
Use this page to figure that out if your not sure (or for others reading this page):
http://wiki.bitcoin-otc.com/wiki/Bitcoin_address_authenticationThen you need to make sure your GPG Key is registered: wiki.bitcoin-otc.com/wiki/GPG_authentication
Then you have to use the following command to provide a rating:
;;rate osok 1
(rate <nick> <rating> [<notes>]) -- Enters a rating for <nick> in the amount of <rating>. Use optional <notes> field to enter any notes you have about this user. <nick> must be the user's GPG-registered username, Your previously existing rating, if any, will be overwritten.
Here is more on the rating system: wiki.bitcoin-otc.com/wiki/OTC_Rating_System