Turn off power to the circuit
Set the multimeter to the correct amperage setting
Move the red probe to the amperage input jack
Leave the black probe in the COM jack
Select AC amps or DC amps as needed
Start with the highest current range
Open the circuit where you want to measure current
Connect the multimeter in series with the circuit
Turn the power back on
Read the current value on the display
Turn off power before disconnecting the meter
Move the red probe back to the voltage/resistance jack after testing