This documentation is not using the current rendering mechanism and is probably outdated. The extension maintainer should switch to the new system. Details on how to use the rendering mechanism can be found here.
To add a Twitterfeed on a page, create a ContentElement and select the Insert plugin option. On the Plugin-tab select the plugin Twitter feed. Choose one of the modes: Timeline or Search and save the plugin to see the configuration for the specified mode.
With the Timeline mode you can display the tweets of one specific user which is specified in the username field. Select the number of tweets to display in the field Tweet limit.
If you select the box Exclude replies you won’t see tweets which are a reply to another user.
With the Search mode you can specify a search query for which to show tweets. Learn how to create queries in the Twitter API Documentation.