So remove the wiper arms, there are 6 clips holding the plastic on to the cowl of the truck. Most of this will be done with hood up, Two torx screws, 1 on each side under the trip pieces. Just slide the passenger side of the plastic cowl cover forward, there is a hatch right there on passenger side, its a known leak place on these body styles, I think this is my 5th on of the NBS and I have had to seal every one of them.
Here is a video on some of the normal places for them to leak. The metal painted door on passenger side is what I am referring to.