I won't bother with pics/details on how to get up to this step other than, of course you need to set the engine at TDC, make sure cams are ligned up, remove the valve cover etc. You don't need to remove the timing belt for this process which is very nice.
Once the cams are lined up and the engine is at TDC, to make it easier on yourself, grab some nail polish/paint marker and mark the marks on the chains on the cam and the one at the pulley for TDC. See the marks I made for the cam chain below. Notice the notch and the arrow line up with each other. Also, it is exactly 16 chain links to and from each notch. So keep that in mind for reassembly.
Next, install the special Audi tool for compressing the cam shaft tensioner. This tool is a MUST to do this job. Tighten it down, but be careful to not to go crazy. You should see slack in the chain once tightened like this.
Next, remove the bearing caps on the intake side. Make sure not to not mix them up or install them backwards. They are numbered which helps. You also need to undo the cam shaft position sensor. Once all the bearing caps are loose on the intake side, I also undid one exhaust cam bearing cap close the cam chain.
The cam probably won't pop right out, so grab a pair of channel locks and and grab the cam on the rough casting (where you won't hurt it) and wiggle the cam back and forth to loosen it. You'll need to remove the 13 mm nut that holds the power steering hose in place. It is located behind the head . Just follow the hose down and you'll see it. Once the cam is loose, you can then rotate the whole cam with chain attached to the side just enough to get the gasket out from underneath it. Reassembly is reverse of removal :)
Once reassembled, you want to rotate the engine by hand to make sure everything is OK. The 2.8 uses 24 MM 12 point socket on the main crank bolt. When you rotate, you'll see the cam chain marks won't line up again, that is normal. Just make sure there is 16 links apart from notch to notch and you are OK.