To publish a single page or file to the web, if you have been granted permissions to do so, click on the publish tab while viewing it. You will then be brought to a page that lists a series of destinations. Unless directed otherwise you should only select the "Production" destination. This will direct your page or file to the correct location on the production server. Then select publish and click submit. The item will then be sent to the workflow to published. You can also use this to remove a page from the web, by selecting unpublish instead of publish.
This can also be done to publish an entire folder. While viewing the folder contents, repeat the same process. If you want a file to not be published along with your site, from the edit->system tab uncheck the include when publishing checkbox.
