Ks and Kr are seperate attributes that you won't really need. You can use the default anim8or Specular box for it, it has the same effect.
as kreator mentioned, the amount of Specular you put on your material, determines the amount of reflection it will have, with 1 being a mirror, 0 having no reflection at all, you might want to play around with it to get the best result that matches the material you are using.
Kreator described how to get a normal reflection going ("New", Attribute: specular, String: reflection). There is also the glossy type that I like to use, since most reflections aren't perfect, but slightly glossy. To make your material have a glossy reflection, make a new attribute, type in specular at the top, and as a 'string', type glossy. (watch capitals, they matter). To change the glossyness of the reflection, you can change the 'rough' value of the anim8or material. again, the specular value changes the amount of reflection. Also you can play with the Brilliance to achieve different effects for different materials.
Make sure the renderer is set to Art by the way! otherwise you won't get any reflections.