How do I compact the contents?

For gravel filled units, the specified 4-15mm clean hard angular aggregate should be fairly self-compacting although a single pass with a light vibrating plate machine or roller may be used to firmly bed the pavers and settle the fill. For grass filled units, the cells should be loosely filled with structural soil (rootzone or a friable topsoil with a very high sharp sand content). Excess soil should be removed and a single pass with a light vibrating plate machine or roller may be used to firmly bed the pavers and settle the fill, but do not compact the soil.