AGX Xavier set up of multiple streams with FPD Link iii

So I was trying to set up D3s multi stream camera and for some reason in the documentation it states you have to go into usr/src/tegra_multimedia_api but when I go into my usr/src I only see cud_samples_v7, Jetson_multimedia_api, linux-headers-4.9.140-tegra-linus_x86_64 Nvidia and tensortt. What can I do to get tegra_multimedia_api ive downloaded Jetpack 3.1. Do I have to download L4T Multimedia API instead if so the tar file gives me a bunch of html files and nlv4t_docs is there some command I have to run in order to multi stream media? Thanks so much!

It is renamed to jetson_multimedia_api. Please cd into the folder and try the samples.