You installed your CKEditor and IMCE but there is only image dialogue on your node edit screen and you want to add plain file link.
Well you need to add to " config.toolbar" in ckeditor ckeditor.config.js 'IMCE' to that setting and in drupal admin screen you can now check box that says "Plugin for inserting files from imce without image dialog (buttons: IMCE)" to activate that plugin as it is present in CKEditor installation, this is for CKEditor module, for WYSIWYG module you will probably have to do more things manually, add plugin to plugin directory if its missing and then add to "config.extraPlugins" in ckeditor.config.js file some data, check read me files then of module.