One Watt is one Joule of energy every second.
So a 1000 Watt generator generates 1000 Joules of electrical energy every second.
A 100 Watt light bulb consumes 100 Joules of energy every second.
An ideal Battery that stores 3600 Joules of energy could release that at a rate of one Joule per second (1 Watt) for 3600 seconds (1 hour) - that is 1 Watt-hour. Or at ten Joules per second (10 watts) for 360 seconds (6 minutes) - that is also 1 Watt-hour.
It may help if you consider Watts conceptually equivalent to Litres per second from a tap/faucet/well/spring/stream and Watt-Hours equivalent to litres in a water-tank/lake.
Watt hours are really a rather odd unit of energy measurement that happens to be convenient for power companies dealing with customers whose education didn't really give them a solid grasp of SI units of energy (99% of people)