In Animation Tools, click on the arrow icon.
When selected, the icon will turn red. To the right, you will find a selection of guides to use in your animation. Click the item you want, the item name will appear in the top left corner of the screen to show it is selected, then place it where you want it on the field.
The default setting for guides is that they stay on the field for two seconds. You can alter this by dragging the outside of the blue bar which will appear on your timeline. If you wish to delete a guide from the field, double click on the black diamond box on the guide and click the bin.