In order to change the message limits you need to access the Forum Administration page. There are two ways in which you can do this. Both require that you are already logged in. If you are not already, click the Sign In link in the utility bar at the top of the screen.

Then either click on the Forum Administration link on the forum's page:

Or, if you are not already at the forum, you can click on the Admin tab at the top of the screen:

Find the forum whose message limits you wish to change and click on the link provided:

You will then be shown the Forum Administration screen. The Message Limits section shows your current message limits:

Use the check boxes provided to change whether users can post high-priority or source messages, and type in the text box to change the maximum size of attachments. When you have finished editing ensure that you click the Change button to save the changes.

Take me to related FAQs:

How do I access Forum Administration?