How can I use clock on cyclone II ?

Hello bianchi.

you don't have an oscillator in a Cyclone device so 2 capacitors and a crystal isn't enough. Electronics components stores like mouser or digikey have integrated oscillators. With Cyclone II i used an SMD 50MHz 3,3V oscillator of ABRACON.

Configure the PLL it's easy. You have a Wizard to do it. Then you instantiate a component pll in your vhdl file. A detail: I use global reset active with '0' and the pll has reset active with '1'. Don't forget the inverter in your design or you'll see it hanged.