If you couldn’t tell from the name of the level, there are a ton of spiked bridges you’ll need to cross. From the start grab the Super Bell from the ? Block then cross the spiked bridge to a Warp Box. Navigate around this area, defeating the Fire Bro until you can head to the end of the long spiked bridge going left where Green Star #1 is easily reached.
Head back the opposite direction then up the cliff to find some spiked bridges that move. You have to be fast and move with the bridge to cross over, eventually you’ll hit the Warp Box. Grab the Checkpoint Flag and cross over using another Warp Box. The arrow says to go right, but if you can make it to the left end the Stamp awaits.
It’s difficult because you have to jump over the spikes as the rise up in a wave and it takes a well-timed leap. Head back to the right and halfway across the bridge grab a Super Bell then climb to the top after beating the Fire Bro. Inside the Mystery Box you need to hit both P Switches then grab Green Star #2 which can be tough be doable. Head back out and finish crossing the bridge to another Warp Box. Head to the far right across this platform to claim a Super Star so you can kill all the Parabones then head up through the spikes and Donut Blocks to snag Green Star #3 before eventually crossing the long spike-filled platforms to the final Warp Box.