hey Alex

I would say there is two ways of doing it .
One ,pop the valve cover off and die grind the chain off, turn the engine over by hand ,and pull it out with the new chain conected and replace the top rail, or...
the way Medcedes wants to with taking everything apart like the manual says, this way is a must if you have to replace
the tensioner rail or any others down there, make sure not to
forget the timing cover gasket part number 102 015 00 80,
or the orange loctite 573 for the seal on porsche engines would
good too