The circuit was meant to be powered by a power supply, which is why there is no transformer, rectifier, or filter capacitors on the schematic. There is no reason why you cannot add these. To use the circuit, hook it up to a power supply/plug it in. Then, connect the battery to be charged to the output terminals. All you have to do now is push S1 (
the "Start" switch), and wait for the circuit to finish. The first time you use the circuit, you should check up on it every once and a while to make sure that it is working properly and the battery is not being over charged.