EDIT - I misread but hopefully this is still of some help..
Way I did it was to disconnect from the MAF including the airbox all the way to part #2
Then silicone part two to the inner wing and let dry
Then silcone what you have left together, leaving the pipe that connects to the airbox free for the time being
You will also need two bottle caps. There's a drain hole at the bottom of the flexi tube and another inside the airbox. A bottle cap and some generous silicone will seal them.
Reinstall & reconnect your airbox
Then get a chunky cable tie and tighen it a little but leave it still loose around part 3
Reinstall all the pipe work you removed as one piece. Be sure to add plenty of silicone before you reinstall, its easier to do outside the engine bay.
Connect everything up and tighten the cable tie at the joint between part 2 and part 3
That should leave you with a fully sealed air system. Leave it the silicone to dry before driving anywhere in case you blow one of the seals you've made.
Leave it at least 48hours then test. Pop the top off your snorkel, start the engine. First thing you should hear air being sucked in. Second test with the engine running block the airway, book, clipboard anything that wont get sucked in. Not your hand!
If it stalls then your sealed. If it runs then there air is getting in.