A Tornado Watch means that current weather conditions could support the development of a tornado. You should continuously monitor media reports for more updates. A Tornado Warning means that a tornado is very likely on the ground and active. Either it's been physically spotted by a reliable source (like a police officer or trained weather spotter), or it's being indicated by wind patterns on Doppler radar.
If a Tornado Warning is issued, you should take immediate action. Seek cover indoors, on the ground floor of a home or commercial building. If a tornado is headed for your community, take immediate cover in the basement. Move to the side of the basement away from the direction from which the tornado is coming. Usually, a tornado approaches from the west or southwest, so in most cases, you want to be on the east or northeast side of the building.
If there is no basement available, move to a first floor closet, or a first floor bathroom, preferably in the middle of the building, or on the side of the building away from the oncoming tornado. Cover yourself with blankets, pillows, or sofa cushions. If no closet is available, crouch along the interior wall of a room on the side of the building opposite from the direction from which the tornado is approaching. Again, cover yourself with cushions or blankets. After the storm has passed, be on the look-out for additional storms.