Boost controller install problem/question

I found instructions on tuners to install my manual boost controller a more effective way. It was talking about installing it on the line that comes from the wastegate to the j pipe.. Now that line is t'ed

It comes from the j pipe and one part goes off (looks as if down to the side mount I can't see...) and the other goes into the j pipe. Which section does it go on? I want to make sure before I would cut the line.