You have mentioned "driver" several times in this thread. I hope you mean "12V power supply", and not something that can flash or dim the LEDs.
So I have to measure the RGB all together to get max amps. Otherwise, it would just be one color at a time.
The manual I could find for your motherboard simply says "2A". If I had written something like that, I would have made it 100% clear whether that was 2A in total, or 2A per channel. In absence of something more definitive, I would take it as meaning 2/3A max for each individual channel (which is more strict than saying 2A in total).
So, while you are about it, check the total and each individual channel. Not that I really expect there to be a big difference between the channels, but a little bit of sanity checking is not a bad thing. The total should be the sum of the three individual readings (provided your power supply keeps the voltage constant).
At one point you mentioned using only 2.5ft of strip, which you said was 36 LEDs. That does not add up, as the strip you got has 60 LEDs per meter, so 2.5ft of it would be 45 LEDs, but either way that should be less than 1A total.
12+ RGB strip"
+ driver---DMM--12+ strip --->
- driver<-- (together, with 3 wires)--RGB side of strip<--

?
To get the LEDs to light up, the positive side of the power supply has to go to the common 12+ on the strip, and the negative side of the power supply has to go to the R, G, and B lines on the strip (clearly, if you want only one colour to light up, only connect that one line, if you want all three to light up, connect all three of them together and to the power supply negative.
Once you can do that, then all you have to do is break one of the connections to the power supply, as Zero999 said either the negative or the positive, and insert your meter in series in that wire.