The end of the drain hose should be in an opening just to the left of the radiator overflow tank and in front of the cabin air filter box. Follow it back under the over flow tank to the black plastic inline drain valve next to the right bank camshaft cover. The valve is just below the red oil dip stick. Be careful not to pull the drain hose off the valve. It's just pushes on the valve nipple.
If you go to wixfilters.com and click on the filter lookup tab, just put in Sprinter for model and the year, the search results will list three numbers for the 3.0L engine. Click on each one to see a picture of the connection configuration. It will be easy to tell which one of these matches yours. If you prefer to use a different brand, just cross reference the WIX number.
As mentioned previously, the filter is located near the center of the engine under the intake air inlet box. You can easily see the top of the filter with a flash light. Look to the right of the camshaft cover in the opening below the air box. It will have a rather large electrical connector and two hoses.
Changing is no too complicated but does require removing the intake air box and a special tool for the hose clamps. The clamps are not reusable.