How do you set post min?
 

I see some forums that require you to have a min post of 50 before using other parts of the forums such as You must have 50 posts in any forum before you can post in the buy and selling section.

How did they do that?

Thanks

You create a new usergroup for users who have more than 50 posts and then you create a promotion to move them from the Registered User group to the New usergroup after 50 posts.