Can I Read How Many Amps Are Being Used W/ A Multimeter?

OP:
The meter you posted requires it to be placed in series with the load. It is rated at 10 amps. I would guess that a lot of the 12 volt DC loads could be in the range of 30-40 amps, which would burn out the meter.
This type of meter can have what is called a shunt. The meter would then be connected to the shunt to get a reading above 10 amps.
On a clamp on style amp meter the cable or wire being tested goes through the ring on top of the meter. It would then read the ampacity. Very easy to use.
Most clamp-ons have the same function as a multi-meter.

Okay I'm starting to get a little confused but I'll research a bit and see if I can clear this up some.

Yes, this one would be better suited for all needs then the OP's meter.
Roy"s meter from Sears

Go to SEARS and look at their CRAFTSMAN CLAMP ON AC/DC ampmeter. Cost around $60..

Looks like this


They also make a AC model only that looks the same so be sure to get the one that measures AC and DC up to 400AMPS...

These are great for measuring DC CURRENT at the +12VDC battery cable.

Top measure AC AMPS you will have to clamp around the BLACK CABLE coming in from Shore Power. The best place to do this is at the AC POWER DISTRIBUTION PANEL where you remove the front panel and clamp around the single BLACK wire coming from the main circuit breaker.

Roy Ken

Meter is only rated 10 amps. That isn't very much especially at 12 volts. I would be looking for one with at least 100 amp rating or have a shunt available as an accessory.
This one would be better.
Klein Clamp on amp probe

Thank you for the quick reply. To do this would I just need to disconnect the positive cable running to the batteries and connect the multimeter between the positive cable and batteries?

Yes you can, however you must break the circuit and place the meter in-line with the circuit, and place in Amps mode.