Batteries should normally be tested under a load because a no load voltage test could read normal, but drop considerably when the battery is under load. This multimeter's manual indicates that the battery test circuit adds 360 ohms of resistance as a load. According to the label on the meter, a 1.5 volt battery in good condition should show a current draw of 4 milliamps or more and a good 9 volt battery should show a current draw of 25 milliamps or more. There is nothing mysterious about this. It is a simple application of Ohm's Law, which says that voltage (E) in a direct current circuit is equal to resistance (R) multiplied by current (I), or E = IR. Factored, that is current (I) equals voltage (E) divided by resistance (R).
Step 1: No Battery Test Function on Your Meter
Step 2: Solder Resistors
See the second photo. I soldered a small alligator clip to one end of the resistors. I slipped a soda straw over them and added some hot glue at each end to provide some physical strength. I scraped the resistor lead opposite the alligator clip to remove any hot glue that might act as insulation.
I could have brought the 367 ohms down to exactly 360 ohms by soldering another resistor of 19000 ohms in parallel to the two resistors. Resistances in parallel function differently than resistances in series. (Adding 19,000 ohms, if such a resistor were to be available, is more of a hypothetical example than a serious suggestion.) Here is an on-line calculator for parallel resistances.
To use, just attach the alligator clip to one of the test leads. Set the multimeter to the 200 milliamp scale. Use the bare resistor lead as the probe. Touch the probes to the battery under test.
Step 3: Make a Label
You can easily make your own resistance load from resistors in your junk box for checking common batteries under load with a meter you already own, even though it may not have a battery test function.