Hello,
Your Mille may have leaked all of the hydraulic pressure out of the system while sitting. It is not out of the ordinary for this to happen. I would simply add more hydraulic fluid at the master cylinder by the lever and then pump it up and bleed at the slave cylinder on the left side of the engine. this process is just like bleeding the brakes. You may have to let the bleeder screw loose at the slave cylinder for a few minutes to let the fluid start downhill.

Thanks and I hope that his helps.
Steve