Fuel Tank With Attachments, Removing And Installing: Installing:

WARNING: This page is about a different car, the 2014 Volkswagen Touareg, 2013 Volkswagen Touareg, 2012 Volkswagen Touareg, and 2011 Volkswagen Touareg. However, it is still accessible from the selected car via links, so may be relevant.

Install in reverse order of removal while noting the following:

Connections for breather and fuel lines must engage audibly when joined.
Make sure ventilation and fuel lines are not kinked when installed.
The flange seal should be replaced each time it is opened.
Secure fuel hoses with spring-type clamps.
Make sure the connectors and the fuel hoses are secure.
The GND wire on the fuel filler tube must be securely attached to the body.

NOTE:

Before fastening the fuel tank, check that the supply and ventilation lines are still clipped onto the fuel tank.