When you look in the edit screen for the rule, you will see variables in the email section.
You have to drag whatever information you want into those boxes next to the variable. For example, if you wanted DetectionIP, you would need to drag that into the box.
Also a side note, when you create email templates, you can make the variable names whatever you want and then assign the information in the rule edit as in the example above. Your variables DO NOT have to be the actual names but it does help when you are editing if they are similar.