How to drag a div with multiples div into another div with n divs and take the coordinates of the div occupied- Javascript

I am implementing the battleship game in JavaScript, and I would like the user to be able to drag their own ships within a 10 x 10 grid, consisting of 100 cells, each corresponding to a pair of coordinates. Once dragged onto the grid, I want to use all the coordinates occupied by the ship to create an object.
This is my HTML with Javascript:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link rel="stylesheet" href="../src/style.css">
   
    <title>Document</title>
</head>
<body>
    <div id="main">
        <div id="deployment-board">

        </div>
        <div id="selection-panel">
            <h1>Drag your ships</h1>
            <div id="ships-dragging-container">
                <div class="dragging-ship" data-length="5" draggable="true">
                    <div></div>
                    <div></div>
                    <div></div>
                    <div></div>
                    <div></div>
                </div>
                <div class="dragging-ship" data-length="4" draggable="true">
                    <div></div>
                    <div></div>
                    <div></div>
                    <div></div>
                </div>
                <div class="dragging-ship" data-length="3" draggable="true">
                    <div></div>
                    <div></div>
                    <div></div>
                </div>
                <div class="dragging-ship" data-length="3" draggable="true">
                    <div></div>
                    <div></div>
                    <div></div>
                </div>
                <div class="dragging-ship" data-length="2" draggable="true">
                    <div></div>
                    <div></div>
                </div>
            </div>
           
            <button id="rotate">Rotate</button>
        </div>
    

    </div>
    <script>
        let rotateBtn=document.getElementById("rotate");
        rotateBtn.addEventListener("click",function(){
            let shipBlock=document.getElementById("ships-dragging-container");
            let shipBlockDirection=window.getComputedStyle(shipBlock).getPropertyValue("flex-direction");
            if(shipBlockDirection =="column"){
                shipBlock.style.flexDirection="row";
                shipBlock.querySelectorAll(".dragging-ship").forEach(ship=>{
                ship.style.width="30px";
                ship.style.flexWrap="wrap";
                ship.style.height="fit-content";
            })}else{
                shipBlock.style.flexDirection="column";
                shipBlock.querySelectorAll(".dragging-ship").forEach(ship=>{
                ship.style.width="";
                ship.style.flexWrap="";
                ship.style.height="";
            })
                
               

            }
        })
        function displayInitialBoard(){
            for (let i = 0; i < 10; i++) {
                for (let j = 0; j < 10; j++) {
                    let cell = document.createElement("div");
                    cell.className = "cell";
                    cell.textContent = i + '' + j;
                    cell.setAttribute("data-coordinates", i + '' + j);
                    document.getElementById("deployment-board").appendChild(cell);
                }
            }
            

        }
        displayInitialBoard();
        let draggingShip=document.querySelectorAll(".dragging-ship");
        for(let ship of draggingShip){
            ship.addEventListener("dragstart",function(){
                console.log("start");
            })
        }
    </script>
</body>
</html>

This is my CSS:

*{
    box-sizing: border-box;
}
body{
    /* display:flex;
    justify-content: space-evenly;
    align-items: center; */
    height: 100vh;
    padding:0;
    margin:0;

}
.cell{
    height:30px;
    width:30px;
    border:1px solid black
}
#main{
    display:flex;
    align-items: center;
    justify-content: space-evenly;
    height:100%;
    
}
#deployment-board{
    display: flex;
    flex-wrap: wrap;
    width:300px;
    height:300px;
    align-items: center;
    justify-content: center;
}
#selection-panel{
    display:flex;
    flex-direction: column;
    height:300px;
    width:300px;
    gap:5px;
}
#selection-panel h1{
    margin-top:0px;
}
.dragging-ship{
    display:flex;
    width:fit-content;
    cursor:grab;
}

.dragging-ship div{
    border:1px solid black;
    height:28px;
    width:28px;
    background-color: pink;
}
#ships-dragging-container{
    display:flex;
    flex: 1;
    flex-direction: column;
    gap:10px;
}

You can run it here:

https://codepen.io/Eligio-Cristantielli/pen/eYQRqxa

Does anyone have any idea on how to implement this in vanilla Javascript?