Turn off the circuit power
Set the multimeter to the correct current mode: A, mA, or µA
Move the red probe to the correct current input jack
Leave the black probe in the COM jack
Select AC or DC current mode as needed
Break the circuit so current can flow through the meter
Connect the multimeter in series with the circuit
Turn the circuit power back on
Read the amperes on the display
Start with the highest current range if the current is unknown
Turn off power before removing the meter
Return the red probe to the voltage/resistance jack after measuring