This level is dominated by series of blocks and platforms that form pyramids. It is inhabited by Pokeys, Spinies, and Fire Snakes.
After jumping over the first goomba of the level, you'll see a koopa under a roulette block. Use the koopa to break the barrier to the right. Alternatively, you can get a Gold Flower from the block and blast your way through. If you are too big to fit, get a running start before crouching at the last moment. Your momentum will get you at least partially through. Inside is a ? block containing a Starman. It will grant temporary invincibility, allowing for the destruction of even normally impervious foes. The nearby Red Ring to the top left will thus be easier to complete. Up and to the left, you will find another small passageway. Go in it to reach the first star coin.
Over the top of the pyramid, you will see a Pokey and then the midpoint flag. The ? block after the flag contains a Fire Flower. Further up and right, you will see a Pokey guarding a yellow pipe. Either rush through and receive damage or destroy it with a power up and go in the pipe. Inside are a Gold Ring and a pair of pipes that spawn goombas. This is a great place to grind for coins, especially if you have a Gold Flower. Once done, you can either go up the pipe to the right, or you can fall down to a platform below. This will take you to the second star coin.
On top of the pyramid you're on right now, there are two floating ? blocks. The one on the left contains a Fire Flower. Over the next hill, hop over the gap with coins and continue down and right to get the third star coin. Then, go back to the pit and jump down. At the bottom will be a pipe, which leads to the flagpole.