Ok, in essence, this is what you do with a diesel Mercedes when you first get it:
1. Do a diesel purge and change the fuel pre-filter and main fuel filter. Inspect all fuel hoses and the fuel tank screen. tighten hose clamps securely if necessary
2. Change the engine oil and filter
3. Remove the air cleaner, see if there is any oil inside, clean it out, replace the air filter. Inspect the air cleaner rubber mounts and the air cleaner bradket.
4. Remove the turbo plastic elbow and inspect the sealing rings on both ends and make sure they are not distorted.
5. Perform ALDA line service
6. Adjust the valves and replace the valve cover gasket.
7. Inspect the vacuum lines for any looseness or leaks
8. Remove the alternator voltage regulator (with negative battery cable disconnected), inspect the brushes, and replace if necessary
9. Inspect the engine oil cooler lines for oil leaks and replace if necessary
10. Inspect the engine mounts and the transmission mount and replace if necessary.
That will do for starters.