Apply it according to the instructions on the label of whatever product you buy. You will either need a clean handsprayer to apply a concentrate you will dilute in the sprayer or the product may come on a hose end sprayer. Either way, follow the label instructions and you should be fine. Do your best to apply evenly.
"The Poor Fish" circa 1930's: The Poor Fish wouldn't have been caught if he'd known enough to keep his fool mouth shut.
"Opportunity is missed by most because it is dressed in overalls and looks like work"- Thomas Edison, businessman/inventor