Over the years the way dishwashers are attached has changed. This is primarily due to the fact that many of the counters people are having installed are granite, quartz, or marble. When formica tops are installed the dishwashers can be attached directly to the formica tops, by being screwed in. With granite, quartz, and marble this cannot be done. Therefore many of the dishwasher companies are making their dishwashers side mountable. If you have a relatively new dishwasher it probably has to the ability to be attached to the side of your cabinet. If you dishwasher is older, or in the rare occasion not side-mountable then we can attached a metal strip under the surface and the clips can be attached to it.
The easiest way to determine if your dishwasher has the ability to be side mounted is to look at the installation manual. It should give you two different options, and one will explain how to attach it to the cabinet rather than the counter. Below is an example of how a dishwasher can be attached to the side of a cabinet.