The document discusses running existing software on Android by either running the binary directly on Android, rebuilding the software for Android, or running the Android system on an existing Linux environment. It provides examples of copying dependency libraries to run an existing binary on Android. It also discusses creating an Android.mk file or using a configure script to rebuild software for the Android environment. Finally, it outlines a process to run the entire Android system framework within a chroot on an Ubuntu Linux system on the target hardware.