Material nodes and bump mapping

So I add a geometry node to map the material to the UV. Then I feed that into the vector slot on the bump texture. Then … What? If I attach that to the color slot on the material it just colors it. If I feed into the normal slot I end up with canyons instead of wrinkles. I’ve searched everywhere and can’t find an answer as to how to adjust the strength of the bump map. Can anyone point me to the right reference?

Thanks