Service A on a Sprinter is
Cabin Air filter change - Trivial to do, no tools required take about 30 seconds
Engine Air filter change - Not hard, requires a T25 driver there should be one in the Sprinter tool kit. I prefer Hengst air filters. While you have the filter our look at the bottom of the air box for debris and a crack. The heat from the engine cracked the bottom on my 2016.
Changing the oil filter and oil is easier than most cars. Diesel Sprinters take 14 quarts of oil so you need a large oil drain pan. Make sure its MB229.52 approved (Mobil 1 ESP 5W-30, or Valvoline European Vehicle Full Synthetic XL-III 5W-30 are my choices). The oil filter is accessed from under the hood on the drivers side near the front. I use Mann oil filters.
https://operatingfluids.mercedes-benz.com/sheet/229.52
Important, the oil minder is set for 20,000 miles. Two Mercedes mechanics strongly suggested I change it at 10,000, or after a year.
The fuel filter recommendation is every 40k. I don't drive that far so I do it every two years.
I had the transmission filter and fluid changed at 40K miles because it was already in the shop for tires and alignment.
The other items on Service A are checking the fluid levels, brake , power steering, coolant, washer, and DEF.
There are plenty of Youtube videos for all the above services.
Coolant flush is not a service A or B item it's at 100K or when the coolant test indicates replacement. The coolant reservoir is replaced when the coolant is changed as it contains a captive preservative packet.