I guess im just missing some chromosomes then, or somethings wrong.No, just no.. please. The walkthrough is indeed confusing in that regard, but you really should use your brain at least a little bit. Of course you have to plant the spycam before, while the bath is empty. Exactly like you did 3 times already.
Planted spycam in cabin - went to pool while mom is there - play blowjob scene - julia arrives - threesome - they go to shower - press the ''follow them'' option - scene plays out - com back later to collect spycam - ''damn nothing captured''