Bill Mollison, an Australian who is widely credited with developing the philosophy of permaculture defines it as:
“The conscious design and maintenance of agriculturally productive systems which have the diversity, stability, and resilience of natural ecosystems”.
Here’s where it all began, The Permaculture Research Institute in Australia: https://www.permaculturenews.org/
Here’s an article by Peterborough Master Gardener, Suzanne Seryck with some easy ideas to get you started:
Here’s a free course on permaculture by Heather Jo Flores, author/founder of Food Not Lawns and a Faculty member of the Permaculture Women’s Guild: