With some effort you'll probably get it roughly level with the bucket but it will be far from smooth. To finish the job you'll some kind of manual leveller. Mine is just a 6' long piece of heavy angle iron with a metal handle (I used 1" galv pipe) welded to it, like a broom handle. Drag it around in circles and figure eights. Put a long board down occasionally with a spirit level to check the levels. Then repeat the process with your clean sand or dirt base. I did this recently to make a pad for a 20,000 litre poly tank. The result was very good.