What did he want to accomplish?

At first Mussolini wanted to delay a major war in Europe altogether, but that changed when Germany invaded Poland in 1939. He joined the Germans even though Italy didn't have a army with enough power to hold out during a long war. He thought that when the French surrendered, he could gain territories from France and attack Egypt.
  
Aside from the gaining territories their were three things Mussolini wanted to accomplish by using the war.
1) He wanted to destroy political structures
2) He wanted to create revolutionary Ideas
3) To gain opportunities for his own glory

Even though the ISP's opposed going into war his headstrong dictator mind made them go in.