I would not surgest cutting the orginal lines, just put them aside and start afresh, if you make a mistake you can always put the originals back on. It is a little involved as you need to tee off both turbos back to one boost controler, if you don't then one turbo will run more boost than the other.
You need to run lines from the fittings (on turbo housing) on each of the turbos back to a tee piece then that single line needs to go to intake of boost controller. Then you need to run lines from the each of the wastegates back to a tee piece then that single line needs to go to the outlet side of the boost controller.
So, boost flows from the turbos fittings along the lines, through the boost controller back along the lines and to the wastegates.
Make sure you use some good quality vacum/boost hose and fittings. This is how we done it on a 1J in Newcastle an it worked OK. Good luck, and if your not sure what your doing get someone who dose to check it.