Be careful because once fried, potatoes can't be kept waiting, covered or not they will go soft.
You should serve them without delay.
Remarks
Brief summary of the method: wash and dry potatoes, coat with a little oil, cook slowly without salt and without stirring for 40 minutes, only then should you salt and stir to cook on all sides.
You will get excellent results with rattes (small firm waxy potatoes), they are already just the right size.
My uncle Pierre, a great chef, when he was chef of his own restaurant, used this dish to test new young cooks.