The HP34401 digital multimeter measures voltage, current and resistance.
There are separate settings for measuring AC and DC values. If you examine the softkey
pad on the lower left of the multimeter, you will find primary functions in black and
alternate functions in blue. The alternate functions are accessed by pressing the shift
softkey and then the function softkey. For example, to measure DC voltage,
you press the DC V softkey. To measure DC
current, you press the shift softkey followed by DC I which is the same
softkey used for DC voltage.
The multimeter also has the capability of measuring other quantities such as
the frequency and period of periodic waveforms. There are three vertically aligned
holes (banana jacks) in the multimeter
located at the top right of the meter front panel.
To measure voltage, place the positive terminal in the top hole, with the negative terminal
in the center hole. The top hole is labeled Hi in red, and V 
in black.
To measure current place the from terminal (the terminal at which
current enters the multimeter) in the bottom hole (labeled in red as I),
and the to terminal in the center hole.
Other than that, the operation of the digital multimeter is
almost entirely automatic, simply set the multimeter to the type of measurement you
wish to make by pressing the button labeled voltage, current, etc. and read the value
from the display.