Hop onto the fence next to where the heart piece box is and activate ISG. Slingshot hover or bomb hover up to the high platform then climb up the box. Activate isg then quickly throw the bomb torwards the seam in front of you to hover off the ground. Now hover onto the seam.
Next you want to get over to the long seam that leads to the shadow temple and stand next to the one where you hovered on before.Now drop a bomb down to the wood box platform and sidehop into the void but shoot your slingshot to cancel the hop so you can take damage from the bomb to hover. Time the sidehop so you get into the bombs blast radius. Do 3 to 5 chu hovers then sidehop into Dampe's grave. Also on a side note, you can avoid doing the sidehop cancel hover by simply aligning yourself a bit torward the void and chu hover over to the graves load zone. (should only take 3 chus) Anyways, once you are in, simply race Dampe to claim your prize.