The Hobbyist's Steam engine is a stand alone engine, capable of running on its own as long as you supply it with enough fuel and water, and a redstone signal. The water inside will boil once the temperature of the engine is at or exceeds 100 degrees Celsius, like boiling water in real life.
It needs approximately 7.6k heat of fuel to reach maximum heat (500ºC) and when at full heat it will burn fuel at a rate of 1k heat each 125 seconds and each 1k heat will generate near 4000 MJ. Maximum output is 1.6 MJ, or 2.0 MJ if an external steam supply is available from a Steam Boiler. It can store 64 fuel, 4,000 mB (4 buckets) of water and 4,000mB of Steam.
To keep the Hobbyist's Steam engine from eventually overheating, it is possible to use an Aqueous Accumulator.
If your engine runs out of water but still has fuel burned, make sure you shut off the power and let it cool otherwise it will explode when you try adding more water to it.
The next tier is the Commercial Steam Engine.