Showing the way the belt should be fitted to the top pulleys.
Although you have the locking pins (VW part number T10074), there is another VW tool recommended for the job: VW part number T10075. To fit this, you should remove the ignition transformer to access the rear end of the exhaust cam. The tool will then fit into the end of the camshaft, allowing you to turn the camshaft to tension it. This job can be done without the extra tool by using a spanner on the front of the cam pulley bolt.
Leave the locking pin in the inlet pulley and remove the locking pin from the exhaust pulley, using the spanner to move the pulley anticlockwise the half-tooth necessary to locate the belt, while keeping the belt on the inlet pulley. Holding the belt in place, turn the pulley clockwise with the spanner – this should not take too much pressure – until the belt is taut and the exhaust pulley locking pin will fit in place. The lower tensioner can then be tightened into position and the main belt fitted.
Once the belt is fitted, you will see that there is no slack in the short run of belt across the top of the two pulleys and that all of the slack has been taken up by the tensioner below the pulleys. As is always recommended when replacing a timing belt, turn the engine two full turns by hand and ensure the timing marks line up before reassembling the engine.
ENSURE BELT STAYS IN MESH TURN PULLEY ANTI-CLOCKWISE TO MESH WITH BELT; WHEN MESHED, TURN PULLEY CLOCKWISE TO LINE UP PULLEY LEAVE THIS PIN IN PLACE PLACE SPANNER HERE REMOVE THIS PIN
This shows the teeth not lining up with the two pulleys.
This shows the slack in the top belt.