The video below shows the process of update page meta keywords (click the button on the bottom right of the video to expand the view). You can also follow the screen shots and steps below this.
Meta Tag Keywords are a list of search terms that are relevant to the service or product your website promotes. The data is held in your websites background code, and is only visable to search engine spiders. The list should be a maximum of 255 characters long and should be separated by a comma e.g. keyword1, keyword2, keyword3 Keywords do not have to be one word for example a keyword could be "boat builders" and plurals can also be employed e.g "boat builder" as this is different search term.