Where is 'forum options' button?

I can't get my private message function to work at the moment and it keeps directing me to 'forum options' to change my settings but I can't find it - can you help?

 Many thanks

 Hi Jessica,

 The "forum options" button is next to the "write a new post" button at the top of the forum.  The options button opens a box at the bottom of the forum that shows options about filtering and sorting the posts in the forum.  Sometimes you will see the message that "this forum has no posts, or all posts are hidden due to a filter, try changing the forum options".  Is this what you're seeing in Private Messages?