No problem! Seeing the comments and suggestions from our game, we seem to have not made it clear enough how to use the hearts.
There is a large heart that can be placed in the chest slot. this is kinda like the health meter. Then there are crates found along the path of the maze that can be used a resources. Merge two of the same saying hearts together by holding one in each hand and bring them together to heal your chest heart after being hit by a corrupted heart. You can carry up to four extra hearts around with you in the other inventory slots on your body. Grabbing a heart and holding the trigger button you can push a heart against the wall. Let go and it becomes a solid climbing hand hold. The resource hearts can also be used to fend off corrupted hearts as they come at you. I hope this helps out!