Turn off power to the circuit
Move the black probe to COM
Move the red probe to the A or mA/µA jack
Set the multimeter to current mode
Choose AC or DC current as needed
Select the highest current range first
Open the circuit so current must flow through the meter
Connect the meter in series with the circuit
Turn the power back on
Read the amperage on the display
If the reading is low, switch to a lower range for better resolution
Turn off power before removing the meter
Return the red probe to the voltage/ohms jack after measuring