won't run

Guessing your looking at a needle and several scales. Ohm's is often represented by an upside down looking horse shoe. After selecting proper range hold probe points together. You will see changing display that will slow down and stop. Where it stops is your O , zero reading of ohms. This is called zeroing the meter.
The meter I use has a digital readout that stops at 0.10 when zeroing. So anything I measure is one tenth lower than shown on display.
Ohm's is a measurement of resistance to electric flow. The test leads themselves have a resistance as well as the meter having an internal resistance. Reason for zeroing , is to know how much adjustment is needed for correct measurement.

Hope this helps , Peter

Analog meters are usually have options to select various ranges. If you are reading
2.5 ohms and the needle has made only a slight movement try the next scale until
you get a reading that causes the needle to deflect better than half scale. Analog
meters are most accurate the closer you get it to full deflection. If needle pegs at
full scale use the next range up. Once you have scale that gives most deflection
without pegging, calibrate meter and take reading.
Click here to see how to use meter .

What is brand and model of meter are you using?