These are generalized instructions.
Since you don't have a thermometer to measure coolant temp, try this:
1. From cold engine start, put you hand on the hose that goes to the thermostat to feel the temperature. It should be as cold as the rest of the engine.
2. Remove your hand and then check the hose a minute or so later. It will feel cold/cool/warm.
3. Keep checking the hose going to the thermostat. At some point it should suddenly get hot.
This means that the thermostat has opened, and the water pump is circulating the coolant.
It will not have anything to do with when the fan(s) come on.
If you feel the thermostat open, and the gauge still reads low, you may need to replace the sender, or check the wiring going to it.
For assistance, go to
Clark's Garage Home Page
Click on "Garage Shop Manual" on the left side, then under the red labeled "Engine" column, scroll down to "Cooling System." There you will find help.