After 2-7 days, your roes will be ready. You now have bottarga. The earlier you use them, the softer they will be; early ones are crumbly and cannot be ground. Let them cure into hardness -- I will often let the bottarga sit for weeks or months -- and you can grind them into the rough powder shown above. This becomes an excellent pasta sprinkle.
Store your finished roe in a sealed plastic bag, vacuum-seal them or put them in a glass jar in the fridge or freezer until you want to use them. Do not grind a piece of bottarga until you want to use it. Just like a spice, the flavor fades once ground.
Bottarga will last a year or more stored this way.