The answer is that you unzip the Arduino wherever you want it to reside, and the Teensyduino installer copies itself into that directory tree.
There are some bugs, the ide opens and closes without error message. You can run it from a command line and see the errors.
The problems seem to be cleared up by deleting two files in your home directory, rm -v ./.arduino/ and ./.teensy/
Here are the specific install instructions:
1. Download the Arduiino software from
https://www.arduino.cc/en/Main/Software
2. Download the Teensyduino, and the udev rules file, from
https://www.pjrc.com/teensy/td_download.html
3. Copy or move the rules file to /etc/udev/rules.d
4. Run the script arduino-linux-setup.sh
5. Run the script install.sh
6. Run the script TeensyduinoInstall.linux64 (or linux32, depending on your computer)
The Teensyarduino install will present a file secltion window. Navigate to, and select, the top level directory that you unzipped from the Arduino tar.xz file.