I am new to this. 1) I hear the system come on, then I hear the furnace fire up then the fan comes on after running for a few minutesit will all shut down, then repeat after about 5-6 minutes. The thermostat is set at 68 degrees is this normal?

It could be normal depending upon how the heat anticipator or program is set in the thermostat. Make sure all registers are open and the return air is not blocked. Also check the furnace filter to be sure it is clean.