how to execute soreprocedure and check it in sql server who's retrun a value

ALTER PROCEDURE [dbo].[ChildDetails]
@ChildId int,
@ChildName nvarchar(100),
@BirthYear int,
@DefaultCurrency int,
@Flag varchar(1)
 

AS
BEGIN
declare @CreatedChildId int
	if(@Flag='i')
	begin
		Insert into dbo.tbl_ChildDetails
					(ChildName,
					 BirthYear,
					 DefaultCurrency,
					 CreateDate)
			  values(@ChildName,
					 @BirthYear,
					 @DefaultCurrency,
					 GETDATE())
					 
		set @CreatedChildId= (select max([ChildId]) from [dbo].[tbl_ChildDetails]) 
        SELECT @CreatedChildId
		return 
					 
		End
 
	Else if(@Flag='u')
	Begin
		 	 update dbo.tbl_ChildDetails
			 set ChildName = @ChildName,
				 BirthYear=@BirthYear,
				 DefaultCurrency=@DefaultCurrency
				 where ChildId = @ChildId
				 and (@ChildName<>ChildName or
					  @BirthYear<>BirthYear or
					  @DefaultCurrency<>DefaultCurrency)
    End
END

You must "SELECT" the values which one you would return, look at the line before the return "SELECT @CreatedChildId".

In an SQL Browser you can execute the Statment like the following "exec [dbo].[ChildDetails] @ChildID=1, @ChildName='Text', @BirthYear=1, @DefaultCurrency=1, @Flag='1'"

Execute as like below in your SQL Query Window

exec [dbo].[ChildDetails] @ChildID=1, @ChildName='Text', @BirthYear=1, @DefaultCurrency=1, @Flag='1'

Do something like this

DECLARE @return_status int;
EXEC @return_status = [ChildDetails] 1, 'Text', 1, 1, '1'
SELECT @return_status;