Are you visual learner? Then start by watching this video. It explains event sourcing in general and how you can use projectors, reactors and aggregates.
Event sourcing might be a good choice for your project if:
your app needs to make decisions based on the past
your app has auditing requirements: the reason why your app is in a certain state is equally as important as the state itself
you foresee that there will be a reporting need in the future, but you don't know yet which data you need to collect for those reports
Some concepts in the package, for example the testing methods of aggregates, were inspired by Frank De Jonge's EventSauce package.