Access shares from iomega home media drive nas

someone says they got the automount to work here Mount NAS share at startup - #3 by favancini1108

favancini1108Jan 30I
had to add this command
"sleep 5"
before the "mount -a" command
so the raspberry waits for the network to be up

thanks anyway

but I have no idea what and where he added the command too. Where would i put this?
Thanks