Wash thoroughly the 250 mL beaker and electrodes with distilled (deionized) water. Your measurements will be erroneous if these are not completely clean.
Cover up any surfaces with newspaper to avoid surface damage on the tabletop, depending on what solution you are working with.
Put the 250 mL beaker on the protected tabletop and add 100 mL of the solution.
Place the electrodes from the conductivity meter into the solution. Make sure that the solution covers the sensory areas of the electrodes. Typically, this is only about 1/2 inch, but it varies with different makes and models.
Give the meter 10 seconds to stabilize and then read the conductivity from the display on the conductivity meter.