How to apply group by instead of distinct when need only unique rows?

I am working on ASP.NET Razor page LINQ to SQL function. I face issue I can't display distinct rows from result returned for viewmodel AssetLPOvm

Desired result

If I have 2 or 3 rows as sample exactly every thing is same and repeated so I need to return only one rows unique or distinct because other rows is repeated .

So exactly I need to return distinct result using group by instead of distinct.

I tried using distinct as below but it not return distinct rows.

So what I do to solve issue?

    public List<AssetLPOvm> GetAllLpoDetails(string SelectedCompany)
    {    
        var AssetBranches = _unitOFWorkAsset.AssetBranches.GetList(x => x.CompanyNo == SelectedCompany && Convert.ToInt32(x.UserID) > 0 );
            
        var NewAssetTagging = _unitOFWorkAsset.NewAssetTagging.GetList(x => x.LPONo > 0);
var result = (from assetBranch in AssetBranches
               join user in Users on assetBranch.UserID equals user.UserID
               join assetTagging in NewAssetTagging on Convert.ToDecimal(assetBranch.LPONO) equals assetTagging.LPONo
     
               select new AssetLPOvm
               {
                   AssetItemNo= assetBranch.AssetItemNo,
                   SupplierName=assetTagging.SupplierName,
                   SelectedMCUName= assetBranch.SelectedMCUName,
                   AssetOwner=assetBranch.AssetOwner,
                   ItemCode=assetBranch.ItemCode,
                          
                   Qty = assetBranch.Qty,
                   LPONO = assetBranch.LPONO
                                }).Distinct().ToList();
 return result;
}

    public class AssetLPOvm
    {    
        public string LPONO { get; set; }

        public string AssetItemNo { get; set; }

        public string SupplierName { get; set; }

        public string SelectedMCUName { get; set; }

        public string AssetOwner { get; set; }

        public double Qty { get; set; }

        public string ItemCode { get; set; }


    }

    public class AssetBranches
    {
      [Key]
      [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
      public decimal ID {get;set;}
      public string AssetItemNo { get; set; }
      public string SelectedMCUName { get; set; }
      public string AssetOwner { get; set; }
      public double Qty { get; set; }
      public string LPONO { get; set; }
      public string ItemCode { get; set; }

       }
    public class NewAssetTagging
    {
        [Key]
        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public decimal ID { get; set; }
        public decimal? LPONo { get; set; }
        public decimal? SupplierNumber { get; set; }

    }
public class User
{
    public string vLoginName {get;set;}
    public string UserName {get;set;}
}

How to make group by to result of function instead using distinct function?

I try with distinct but not return distinct rows.

Group by all columns , you can have a try:

.GroupBy(p => new {
    p.AssetItemNo,
    p.SupplierName,
    p.SelectedMCUName,
    p.AssetOwner,
    p.ItemCode,
    p.Qty,
    p.LPONO}).ToList();