Don't continue the path to the colour labyrinth yet. Go to the right, up the wooden path and SMASH! a couple of blocks to be able to go right to the chest next to a cannon.
Use the cannon to get to the Secret Chapter. Cross the first battle area and head to the right. SMASH! the boxes until you find a chest. Then hit the grey button to cross over again.
Go through to the next area by opening your paths with the blue buttons. On the other side, SMASH! the pipe entrance. Don't go through. Go to the left and find the statue by SMASH!ing the boxes. Take the statue back to the pedestal. That'll open the path to the second battle. Cross the battlefield.
Hit the blue button - that will open the blue wall at the pedestal - and go through the other pipe to pick up the chest on the other side.
Go back through the pipe, where the blue button is. Make sure, the block next to it is UP. Cross the battlefield and go to the area where you moved the block around. The wall around the second pipe should be down now. Go through it.
Next we go right. You need the yellow labyrinth to cross to the right. Then move the block onto the blue square. Go around the little island (the walkway appears from nowhere as you go along) to get to the chest.
Back at the labyrinth colour selection, choose green at the top so you can continue with the story. After the fights you end up at the start of the Thorny Vale. Right in the left corner is a chest.
Also at the far center back of this labyrinth there are a couple of blocks to SMASH! When you did, you'll see that you can move one block so the door opens. Walk inside and go over the gap. A walkway will appear so you can cross to the other side and take the pipe up. Now you can get the statue off the appearing walls. Take it back to the pedestal and go get chest 1 of 2.
Finally, we're leaving this labyrinth and continue the story path. Close to the Challenge 8 Rabbid, there is an area that you have to SMASH! open to get to 1 of 2 chests
Continue the story path and go to the start of the next battle area. Keep left. There is a path up, where you have to SMASH! your way through to get to the chest.