Answer:
Near the beginning of the act, after the part with the giant rocket, the player will go up some platforms with Egg Pawns and the first Red Star Ring in plain view.
(Yellow Drill needed) After the first checkpoint, the player should break open the Wisp Capsule containing a Yellow Wisp, then continue right. After going through the loop, they must drill into the ground just before the Dash Panel, then go down to find a square of Black Mounds with the second Red Star Ring in the center.
(Yellow Drill needed) After obtaining the second Red Star Ring, the player must drill down to the area below, then continue right and jump up some platforms until they grind over a short rail. They should stop there and go under it, back to the left. They will then get to a small area with the third Red Star Ring.
After the second checkpoint, the player should go to the end of the path where the giant rockets come from and jump right, but avoid the springs. Instead, they must walk to the right to find the fourth Red Star Ring.
After collecting the fourth Red Star Ring, the player should go to the end of the second path with the giant rockets, but avoid hit the springs. Instead, they must look behind them for the fifth and final Red Star Ring.
