Add just enough HOT water to make the compressed, dry, blocks expand, and if you must, break up the dryish lumps by hand...don't add anymore water than you need to. Let this stuff rest, in a bucket, for a few hours to evenly soak up the moisture.
Good for starting seeds, storing cuttings, and for air-layering fig-tree branches. If it drips, it's too wet...it should be barely moist.
Frank