On the table of Captain

how is it obtainable????????????????

In order to get this knowledge you have to play the full main questline, you cannot get it using the simplified questline that is available for a season char. When you get to the Heidel crossroad you have to select the LEFT option, which is called "The Lamenting Head of the League of Merchants" ( https://bdocodex.com/th/quest/21004/1/ ).

You then continue to play through the questline all the way until you get to the category "[I] Apparent Ambition". The fifth quest of that category is called "Delivery of the Operation Orders" ( https://bdocodex.com/th/quest/21013/4/ ). You can then interact with the Operation Orders on the table. This gives you the knowledge for "Delphe Knights Operation Orders" ( https://bdocodex.com/th/theme/6155/ ). You then run over to Margaret and chat with her. This gives you the knowledge for "Order Delivered to Margaret".

解主線 --- 在賽林迪亞主線中分支選第一個[選擇]商人會長的苦衷，接著一直解到一個任務叫轉達作戰指令書，然後你可以和桌上的作戰指令書互動得到一個知識叫「戴爾佩騎士團作戰指令書」，然後你就可以去找瑪葛莉對話獲得「轉達給瑪葛莉的指令書」知識。