Day One - An-Sar/PrimalCore GitHub Wiki
To get started you will have to follow a few unique steps. You're first goal is to make some initial flint tools that will allow you to harvest wood, processing plant materials, and begin the normal crafting experience.
Unable to effectively collect wood logs without a tool, you will begin by gathering Plant Fiber, vanilla Sticks, and Vanilla Flint. The fiber will drop from a variety of plants, such as grass, tall grass, and vines, additionally once you have a Work Blade a variety of other items will be able to produce fibers. Sticks are found by breaking leaf blocks. And finally flint drops normally from Gravel, and also has a small chance of dropping from dirt and sand.
Plant Fiber allows you to craft Twine, which in turn when combined with the other items you have collected gives access to some initial flint tools.
Your main priority will be to acquire a flint hatchet, crafting table, flint saw, and a flint work blade. These basic items will open a wide variety of early game recipes, such as processing logs and plants into more useful items.
The details of these recipes can be found through JEI
Flint will need to be flaked in order to be used for crafting, you can read about the details obtaining Flaked Flint
Here is an overview of the most notable Gameplay Changes