Fill out the table with words in C# WPF

I am new in C# WPF and am trying to create a WordPuzzle game. I created a 10x10 table and randomly inserted a letter into each cell. Here is My C# code:

public partial class MainWindow : Window
 {
     public ObservableCollection<ObservableCollection<char>> Chars { get; set; }

     public MainWindow()
     {
         InitializeComponent();
         DataContext = this;

         Random rchar = new Random();
         Chars = new();
         for (int x = 0; x < 10; x++)
         {
             Chars.Add(new());
             for (int y = 0;  y < 10; y ++)
             {
                 Chars[x].Add((char)rchar.Next(65, 91));
             }
         }

     }
 }

How do I put the words in the table I can’t figure out?

thats how my grid look