Two options depending on how ugly you like your script babies to be:
a) Create /storage/.config/autostart.sh and place some commands there; the script is executed at the start of userspace boot and is blocking but you can (background)& the commands and prefix with a sleep value to have something execute 10 seconds after boot (or whenever, you control the sleep value). This is the ugly kid.
b) Create a systemd .service file in /storage/.config/system.d to run commands or call a script; systemd gives you precise control of when the service is executed in the startup/boot workflow. This is the better way.