To animate a line graph in PowerPoint, you need to open the slide, draw the Graph add the labels and then animate the graph as explained here.

We show you how to create a Histogram chart in Microsoft PowerPoint. A Histogram is a graphical representation that shows frequency data.

How to Make Graphs to Put Into PowerPoint. Microsoft PowerPoint enables you to create presentations and slide shows. While a wide variety of text-, image- and object-editing features are available ...

Start the PowerPoint application and use the "File" menu to open the presentation containing the graph to which you wish to add the callout.