Once you know true landed cost per unit, set your selling price to cover it plus your target margin, plus a buffer for costs that vary shipment to shipment, such as demurrage on a delayed container. Calculate your break-even volume: how many units you must sell to cover the fixed costs of the shipment, such as forwarder minimum fees, before you start making a genuine profit.
If your purchase is priced in a foreign currency, a shift in the exchange rate between the day you agree the price and the day you actually pay can change your landed cost meaningfully. Either build a currency buffer into your pricing or explore forward contracts and other hedging tools through your bank once your import volumes justify the extra complexity.