the 2000 series volvo has a spin on filter located in front of the motor on top. Remove it just like your oil filter. Have some rags handy to catch any spilled diesel.
After you change out the filter, you will need to bleed the fuel system, using the small valve on top of the filter bracket.. I always open the decompression lever and crank the motor until the air is pushed out, then closing the valve.
Close the decompression lever and the volvo should start right up. Attached is a handy spec sheet. Good luck