If you try to measure amperage with the resistance (ohms) circuitry in your meter, you'll blow the fuse again. When using the resistance portion of the meter, the meter itself provides a minute voltage that it puts through the circuit being tested. The amount that this voltage drops reflects the amount of resistance in the circuit.

Using an instrument to detect battery drain requires that the user fully understands the capabilities (and limitations) of the measuring device. See if you can find the instructions for the meter and follow them. Remember, an electric clock will draw a small amount of current (as would the dome light if the door is open during testing).

Good luck with your troubleshooting.

Wes