[MWAN3] restart if no connection

Hi, I'm new to openwrt.
Installed it on my r6220 and using 3G modem for connectivity.

But the problem is, the 3g connection is not that stable. it often disconnect (once a day in average).
it'll reconnect if I issue the command /etc/init.d/network restart
So I was looking for a way to automate the process where it'll execute the above command if no internet connection.

I searched and stumbled across mwan3 hotplug script, but don't have a clue how to make it work.

Can anyone please guide me how to set it up?

OpenWrt SNAPSHOT r7700-fecbd91c7c / LuCI Master (git-18.211.72541-26bbd01)

here's my mwan3 screenshots: