update readme

README.md

@@ -8,7 +8,10 @@ Please use instructions on our [project page](https://www.cmu-exploration.com/ta
 
 ## Usage
 
-The repository has been tested in Ubuntu 18.04 with ROS Melodic and Ubuntu 20.04 with ROS Noetic. Due to usage of [OR-Tools](https://developers.google.com/optimization) library, the code only supports AMD64 architecture and currently does not compile on ARM computers. Follow instructions in [Autonomous Exploration Development Environment](http://cmu-exploration.com) to setup the development environment. Make sure to checkout the branch that matches the computer setup, compile, and download the simulation environments.
+The repository has been tested in Ubuntu 18.04 with ROS Melodic and Ubuntu 20.04 with ROS Noetic. Due to usage of [OR-Tools](https://developers.google.com/optimization) library, the code in default branch only supports AMD64 architecture. On ARM computers, please download the corresponding binary release for the target platform, for example, [or-tools_arm64_debian-11_cpp_v9.8.3296.tar.gz
+](https://github.com/google/or-tools/releases/download/v9.8/or-tools_arm64_debian-11_cpp_v9.8.3296.tar.gz), extract it, and replace the ```include``` and ```lib``` folders under ```tare_planner/src/tare_planner/or-tools```. 
+
+Follow instructions in [Autonomous Exploration Development Environment](http://cmu-exploration.com) to setup the development environment. Make sure to checkout the branch that matches the computer setup, compile, and download the simulation environments.
 
 To setup TARE Planner, clone the repository.
 ```