Head right to the 3D Warpstar and ride it back to the next ledge. Continue riding the stars back until you reach and enter a doorway.
In the cavern, head right and hit a bomb to clear some blocks. Descend a ladder and head left from its base. Break more blocks and descend another ladder as enemies leap into the picture. You can go two ways here. Left lies food, while to the right you can find another ladder. Descend it to reach a 3D Warpstar that you can ride back one ledge.
Now start to the right. You can jump in the bowl of water and tilt the 3DS to the sides to pour liquid left or right. Pour it to the right to put out the blazing fire. Water will wash over the area and reveal a door. Enter it.
In the new chamber, head right to the 3D Warpstar and proceed past it for a moment. Past some enemies and a cannon, you'll find a 3D Warpstar at the far right end of the passage, along with a Keychain. Use the star to head to a front ledge, then proceed right to find another 3D Warpstar. Ride it back and then kick your way left to reach a treasure chest. Open it for a Sun Stone. Then continue left and ride the 3D Warpstar (near the cannon) back to the foreground. Keep this location in mind. You'll be returning shortly, following an optional detour.
The detour calls for you to backtrack to the far left here by hopping along the foreground ledges. You'll arrive at a dead-end room where you can see a swordsman and a 3D Warpstar. Inhale him for the Sword ability if you want it, then ride the star to the background. Break the blocks for cake and a 1up, then head back into the foreground and return to the area I told you to keep in mind a moment ago. Now you're ready to continue to the right.
As you head right from the cannon, along the foreground platforms, you'll see the star that led you to the background and allowed you to collect the Sun Stone, along with a ringing bell. If you continue right from here, you'll reach a switch. You can drop through a ledge to hit it, which makes a ledge disappear in the background. Head right to the 3D Warpstar and ride it back to the ledge, then pass through the new opening to reach a door. Enter it.
Now you should hop into the cannon with the red arrow pointing up. You'll blast through an obstruction and land in a blue cannon. You can tilt the 3DS left or right to adjust the angle at which it will fire. Tilt left and fire through an enemy to collect a Keychain. Then you'll be returned to the cannon. Follow the line of cannons as indicated, to reach another blue cannon situated beneath a number of overhead blocks in a steeple formation. Tilt that cannon left and pass through another block for the level's second Sun Stone. Then hop up through the overhead ledge to find another cannon. Ride this cannon up to a new door, which you should enter.
In the new passage, head right and gulp down the cat-like enemy to gain the Whip ability. Use it on blocks as you head right, to drop cannons out of your way. You can also reveal a glowing doorway in this manner. Enter it to find a puzzle room with a Sun Stone. There's another glass bowl here. Jump in, and tilt it left and right to water plants and grab a Key. Use it to open a gate on the ledge overhead so that you can grab your loot. Then exit back into the main chamber.
As you continue right past a swordsman and ascend a passage, break a block to your left at the very top for another Keychain. Then head right to enter another doorway. Break the blocks, drop down and continue right. You'll see a Bandana Waddle Dee on the back ledge that will toss you a reward in the form of an Assist Star, the quality of which varies depending on your StreetPass use. Continue onward from there to receive your choice of Fire or Sword weapons (the former is the more useful option). Then fight a boss just to the right.
NEXT: Fine Fields - Stage 3