Valid for Moodle 2.8. Updated on 7/21/2015.
There are two methods for selecting content to add. You can switch between methods when editing is turned on by going to the Administrative block and clicking on the option Activity chooser on or Activity chooser off.
Pull-down menus (Activity chooser off)
With this method, once you've turned editing on for a course using either the button in the upper right or the option in the Administrative block, each section will have two pull-down menus, one for resources and the other for activities. Simply pull down the appropriate menu and select the type of content you want to add.
With this method you have a single link at the bottom of each section.
Clicking on link brings up an interface that allows you select the type of content to add by clicking on the appropriate radio button and then the Submit button. The advantage of the activity chooser is that for each activity/resource it provides a brief description on the right. The disadvantage is that is requires more clicks and often some scrolling. In our example, all the resources and many of the activities require the user to scroll down.