DC 6.5-100V 0-100A LCD Digital Display Ammeter Voltmeter Multimeter Volt Watt Power Energy Meter Blue with 100A/75mV Shunt

I bought above mentioned item from amazon site.

Application am using for is to check the dc voltage and the amp rating for cctv cameras.

cctv camera runs on dc voltage of 12v and amp ranges between 1.5 – 5 amp.
we want to check if the cctv camera is receiving proper voltage and amp over long cable run.

For that purpose do I need to use the SHUNT.

Also I bought:
DROK 0.28″ DC 0-100V 10A Digital Current Tester Gauge Red Green Bright LED Display Five Wires Volt Amp Meter for Solar Battery Monitor Car Motor Panel Mount and want to use for same purpose. on the wiring diagram RED/BLACK wires are power source, on the load side do I need to use YELLOW wire to test load.

Thanks