When the debug agent is connected to the host debugger, you can transfer files between the host and target systems. Note that this is a general-purpose file transfer facility — it's not limited to transferring only executables to the target (although that's what we'll be describing here).
In order for Neutrino to execute a program on the target, the program must be available for loading from some type of filesystem. This means that when you transfer executables to the target, you must write them to a filesystem. Even if you don't have a conventional filesystem on your target, recall that there's a writable "filesystem" present under Neutrino — the /dev/shmem filesystem. This serves as a convenient RAM-disk for downloading the executables to.