It is a tempstar model number nugm050efa1 about 8 years old. How do I check out these things

Usually a blown motor will smell, or be hard to turn manually, (the blower wheel). Also, you can touch a 120v wire to any of the furnace wires except white, and leaving the white wire hooked up to (common), it should start. You need to take caution in doing this, as electric shock is always a possibility when dealing with live wires, so I usually make the connections with all power off, and then when secure, apply power for a second to see if the motor will start up. An amp meter is invaluable also, as it gives an indication of startup and run amps which can be of use when diagnosing. Occasionally the capacitor is all that is wrong, but if this condition persists very long, soon the motor will go out anyway.