where to put mount.sh file?

[Gerhard Magnus]

I've been experimenting with setting up an ftp server on a home network.
The instructions I've been looking at for getting vsftpd operational
include using "mount --bind" commands for mounting other directories
to /var/ftp (neat trick!) The how-to says:

Whenever you restart your computer, you have to bind the directories
every time, so that they are shown on the ftp server. To skip binding
every time, write everything (all commands for binding) in a mount.sh
file and run it whenever you restart your computer.

Confession: This will be my first unix script. A whole new world awaits!
Where do I put it?
How do I guarantee it will be run at boot time?

Thanks for the help!
Jerry