Bushcraft is an art form. It is essentially the knowledge of using outside or natural resources to survive and thrive. Many wilderness lovers have more skills than they do tools when it comes to surviving outdoors and bushcraft as a whole is a set of skills that can do much more than many tools can.
Learning it is something that you will need to take time doing. There are excellent resources and communities online for those who are just getting started or who need to know if that mysterious nut they found is edible or not. Food foraging is the most essential skill next to shelter building, hunting and water gathering.