On the right side of the ESM UI there is a pane called the Filter Panel. This panel allows you to enter criteria that will filter your view. For example, if you only wanted to see events from a single IP address, you'd enter that IP in the Source IP filter field, and refresh the view.
In order to apply a watchlist as a filter (as I discuss in the blog post you've referenced) you'll need to click on the funnel icon next to the field you'd like to filter on. A tabbed dialog will appear, with one tab labeled "Watchlist". If you select this tab, you'll get a list of all the appropriate watchlists you have defined, and you can select one or more of them to use as a filter.
Hope this helps. Good luck!