If you’ve followed the install instructions from your link, installed all dependencies, you wouldn’t need the sources tarball until you want to customize and rebuild yourself.
You may just set up the environment for the path where you’ve installed the triton server binaries:
TRITON_SERVER_DIR= <where_ever_you_installed>
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$TRITON_SERVER_DIR/lib
export PATH=$PATH:$TRITON_SERVER_DIR/bin
tritonserver
Note there will be a webinar for more details about triton with Jetsons.