Can I add additional cover on a new Amana condenser unit (outdoor) that seems to have inadequate cover?

All modern condensing units are designed and engineered to withstand the elements in a normal outdoor environment. There is no need for an additional cover. If it makes you feel better, you can have a canvas cover made to protect your unit during off times. All condensing units require yearly maintenance which would include the removal of dirt and debris. In most cases this can be accomplished by either yourself or a AC tech, The parts that you are able to see while looking down into the unit are weather resistant.