Dishwasher Not totally draining.

I am not sure of the exact age on the dishwasher but we have a GE profile and their is water in the bottom not draining completely. I have searched looking for a manual online and only found other model manuals. Please if someone can help me find the problem that would be great! I am not sure what needs to come apart to check on this but I have repaired other appliances after researching online with no problem. I just need a little guidance please. Thank You