you can set permissions for forums by going to admin>>>forums>>>category and forum management then click the little cross and tick icon to the right of each forum beside the orange cog to set permissions for members.
You can allow users to edit/delete there own posts by going in admin panel=>Forum=>Permissions=>Forum permissions control and choosing a topic/topics you want and edit the permissions for it like this: make sure that "Edit its own messages" box and "Delete its own messages" box are selected for members.