How is a generator made?
A generator is very similar to motor just that is the other way around. It is used to convert mechanical energy into electrical energy. To make electric energy you need a copper wire, a magnet and something to power. The copper wire has to be wrapped around the magnet. If the magnet turns it will make the electrons in the wire start flowing around. The electrons flowing through the copper wire create electric energy which will power what you have to power.
How is it similar to a motor?
A generator is very similar to a motor. It is a motor just that upside down. A motor is used to change electrical to mechanical energy and a generator is made to change mechanical energy into electrical. Both are to transform types of energy into others.
Generators are used everywhere now a days. Some examples are the dams (hydroelectric plants) that make the water current hit some turbines that create electric energy. Also windmills that are being turned by wind currents are making electric energy. Finally a third example are the small generators used when there are power outages and stuff like that which change the chemical energy from the gasoline to mechanical energy to electric energy so you can have electricity.