From the home screen, click the '+' button at the top right, then click 'Create Story'.

Select the Group that contains the datasources you need for your Story. (To learn how to add datasources to Groups, see 'What is the Data Factory and how do I add datasources to a group?') 

Your Story is now created in the selected Group. On the edit screen, select 'Setup Data' at the top of the left toolbar.

Under 'Datasources', click 'Select Datasources'. A menu will appear on the right. Tick the datasources you want to include in your Story. You can search for datasources by name in the search bar. You can also filter them by platform and auth token by clicking 'Filter', selecting your criteria, and clicking 'Apply'.

After selecting your datasources, click 'Apply' at the top right corner of the 'Select Datasources' menu.

Your selected datasources are now listed under 'Datasources' in the left toolbar. All nugits in your Story will pull data from only these datasources.

From the home screen, click on the pencil icon on a Story to edit it.

Click 'Setup Data' at the top of the left toolbar.  Click 'Select Datasources'. A menu will appear on the right. Tick the datasources you want to include in your Story.

To see all datasources instead of only the datasources you previously selected, un-tick 'Show Selected' at the top right of the list. When you have selected the datasources you need, click 'Apply' at the top right corner.

You can also remove a datasource without using the 'Select Datasources' menu. Click 'Edit' above the list of datasources in the left toolbar. Click the trash icon beside the datasource you want to remove from the Story, then click 'Done'.