Drag the logs from the trees you punched into the 2x2 crafting square on the left of the arrow. Planks will appear to the right of the arrow, click these to pick them up.
Now take the planks, and put one into each square of the crafting square to the left of the arrow. This will make a crafting table, which you need to craft almost everything in the game.
To use your crafting table drag it to the bottom row of your inventory. This puts it on the quick use bar. When it is on the quick use bar you can access it outside your inventory screen by pushing the number associated with the square, or using your mouse wheel to scroll through all the items on it. When you have the table in your hand right click on the ground the set it down. Finally to use it right click on it to bring up a bigger crafting 3x3 crafting square.