Sorry to keep you waiting for a response. The process is to click the tag in the "Get Tagging" menu and then to click on the image of the diary page where you want to put the tag. A dialog should open where you make a select or enter information.
Sometimes you will find there is a time lag. You might need to wait a second or two between selecting the tag type and clicking on the image.
Does that help? If not let me know and we will dig a bit deeper.