There are 8 coins hidden throughout the game. A new chapter begins whenever the screen fades to black and each chapter has 1 coin in it aside from the last one, which has 2... I think. It's a little hard to keep track while you're in VR and the coins permanently disappear once collected so I can't go back to double check.

Just gaze at the coin for a second and it will be collected automatically. A short animation will play out indicating it has been collected. There are achievements for collecting 4 coins and all 8 coins.

Coin 1, back of the wagon:

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Coin 2, barrel near pelts:

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Coin 3, on the wood bundles:

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Coin 4, bottom of the stairs:

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Coin 5, on the pelts:

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Coin 6, behind you, on the well:

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Coin 7, on the corner of the brick oven:

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Coin 8, behind you, on a crate: