How do I get my heat to come on?

My wife and I just bought a house with an oil boiler. Since we came from a condo with electric heat, this is new to us. We get hot water, but the baseboard heat doesn't seem to come on. The temp in the house last night was 64 and I had the thermostat set at 69, so it should have come in. Is there most likely a switch somewhere that will activate the baseboard?

Thanks for the help!

Mike