As above fuel filter located under the plastic covers under the car below where the drivers feet would be.
Elsa win is the best source of information by far it's what the dealers use. Available off Fleabay.
On these cars there is a process to go through to bleed air from the system.
From ElsaWin
Caution
If components of the fuel system between the fuel tank and the high-pressure fuel pump are removed or renewed, the basic setting âChecking fuel system pressurisation pumpâ must be performed to bleed the fuel system.
If the supplementary fuel pump, fuel line (between fuel tank and high-pressure fuel pump) or fuel filter is removed or renewed, the basic setting âChecking fuel system pressurisation pumpâ must be performed before the engine is started for the first time.
Proceed as follows to fill fuel system with fuel:
â Connect a â Vehicle diagnostic tester.
â Switch on ignition.
â Select âEngine electronicsâ in vehicle self-diagnosis.
â Then select âBasic settingâ.
â Select âChecking fuel system pressurisation pumpâ from the list.
â Press âStartâ button.
â The fuel pumps start running.
â The fuel pumps must run for approx. 1 minute to ensure that the fuel system is filled sufficiently with fuel.
Note
To repeat basic setting, switch ignition off and on once. Then start basic setting again.
â Start engine after filling fuel system.
â Run engine at moderate speed for several minutes and then switch off.
â Check fuel system for leaks.
â Erase entry in event memory using diagnostic tester.
â After completing the repair, road-test the vehicle. Accelerate with full throttle at least once. Then check the high-pressure section of the fuel system again for leaks.
Note
If there is any air left in the fuel system, the engine may switch to the backup mode ('emergency running' mode) during the road test. Switch off the engine and erase the event memory. Then continue the road test.
You can do this with VCDS
Karl.