1. I widened the trench that was one of the rain ponds and piled the topsoil to one side. (Those guys in the States used a JCB for theirs, but as mine is only about two metres long and one metre wide, it seemed an unnecessary luxury here.)
2. I piled the logs, acquired earlier, into the trench, and made several more trips to gather some barrows of smaller brushwood and branches to put on the top. It made quite a respectable sized pile.