as @wo3 said, after you set the disc to read/write you should be able to make changes to the disk.
When my Organelle shipped (YMMV), there was a folder called
/root/scripts and inside was a bunch of convenience scripts, one of which is
remount-ro.sh, which mounts the disk as read/write and read respectively. There's other stuff in there, too, and it's a good place to store your own scripts as you make them.