Start by going around the far side of the cleat from the load and putting a turn around the base. Going around the base gets friction working in your favor, this allows heavy loads to be held with ease.
Take a turn under the first horn and secure the line with a weather hitch on the 2nd horn.
The underhand half hitch is called the Weather Hitch and is used to lock the cleat.
In a hurry or need to make a quick getaway? Omit the Weather Hitch and just use several “8” ‘s.
Don’t use more than one Weather Hitch.
High loads, highly polished cleats or mismatched cleat and line size? Take an extra turn or two on the horns (not around the base, an extra turn around the base can jam) then finish with a Weather Hitch.
Do not use a Weather Hitch if the cleat may need to be released under load or in a hurry (such as towing or when in the Locks).
See this article for How to Tie a Cleat with pictures.