The first area. After dropping in, listen to Bowser and continue to the right. You will find a "mentor" named Blocksty. Listen to him and press up infront of the door.
After completing Area 5a, head back here and hit the two Red Toad blocks in the middle.
Head right until Blocksty appears. Hit the blocks with your head and jump up to the door.
After 5a, two Toad Blocks are among the blocks here.
Listen again and hit the ? Block. Take the hammer and break the block wall. Jump up the go-through platforms and enter the door.
After 5a, a Green Toad is behind a wall of blocks. A Red Toad block is among the blocks again.
Take your hammer and hit the wall switch. Ride the platform to the top, and pull the switch. Jump to the pressure plate, grab the key and jump to the locked door.
After 5a, throw the key back down the platform shaft to activate a pressure plate, making two Red Toad blocks and the Key appear.
Jump accross the platforms and take the Fire Flower. Jump back and throw the fireball into the hole, causing a chain of event. Jump down on the deactivated spikes and find the door. Jump to the right to find a hidden block with the key.
After 5a, burn the wood blocks beneath the platform to reveal a Blue Toad and a Green Toad.
Blocksty shows a presentation about the Toads in the area: Red Toads can teleport away, Green Toads follow the player to the end, and Blue Toads must be brought to the end by being carried.
Jump over or on the Goomba and pick up the Glow Block. Throw it at the switch and run back to the platform. At the top, avoid the Spinys from the Lakitu and pull the switch. Time your movements to avoid the spiked balls and make it to the platform. Jump on it to lower it and find the unlocked door.
Use a Glow Block to direct a Spike Ball into the wooden platform, leading to a Red Toad.
A secret shaft is behind the door. Jump down and find a Red Toad block.
Head to the left and find the hidden alcove. Collect the Frog Suit and continue left until you find a high ledge. Jump up and throw the key onto the pressure plate. Climb the ladder quickly and hit the switch. Find the key inside the box and open the door.