88' w124 Fuel issue

[SKYDAWG]

Just got a squeaky clean 260E with all original docs and records From the original owner I have known for 15 years. It needs a fuel filter and I have no Mercedes experience but want to do it myself.
1) Where is the filter located and
2) I need a manual for this vehicle.

I ws told it was a frame mount pump and filter but it is not on the frame. Is it under the trunk pan near the tank, or under the hood?

1 - 10 how difficult is the replacement?

Thanks for helping a newbie!