How to Get Planks Without Punching Trees
Gather Loose Materials First
You cannot punch wood into planks. Break grass and leaves by hand to collect Plant String, and pick up any loose sticks and gravel you find. Gravel gives you flint, which is the key to your first real tools.
Craft a Flint Axe
Combine flint with sticks to make a Flint Axe. This is your woodcutting tool. Use it on tree logs to harvest wood. Once you have logs, you still cannot turn them into planks with your bare hands.
Use the Saw
Craft a Flint Knife, then use it to shape wood into a Saw. A Flint Saw lets you cut logs into planks. Place a log and use the saw to produce planks. Higher-tier saws (Iron Saw, Gold Saw, Diamond Saw, Netherite Saw) cut faster and last longer, but the Flint Saw is enough to start.
Alternative: Knife Cutting
A Flint Knife can also process wood in a pinch. Use the knife on logs to split them into planks. This is slower than a saw but works before you have the materials for one.
Scale Up
Once you have planks, build a crafting table and expand. Upgrade to an Iron Saw or better as soon as you have iron. Keep Plant String handy — it is used in several early recipes and is easy to overlook.