Unfortunately, the diagram in the link does not apply to Audi V6 engines.
In Audi's 6-cylinder engines, the first cylinder is located on the front passenger side.
On the right side of the vehicle, the cylinders are arranged from front to back as follows: cylinder 1, then cylinder 2, and finally cylinder 3.
Then, on the left side, you'll find cylinders 4, 5, and 6.
It's quite easy to determine, for example, by checking the part number on the valve covers.
059103470Q Cylinder head cover, right side, cylinders 1-3.
059103469AA Cylinder head cover, left side, cylinders 4-6.
Regards,
Mpire