To add a new guide to the slide press and then drag an existing guide

To be able to add new guide to the slide, press [Ctrl] and then drag an existing guide. Make sure that the guide is visible to your power point first so you can be able to do this. Guides in the power point is consist of 2 lines, the horizontal line and the vertical lines, once this set to appear, it will be visible to all your slides. 

Ireally like network models.