How to execute a transaction within a Command

I am making an application that will register an order and for that I need to use the transaction sentences. I have developed an attempt that I will attach below and the following error:

  

Unhandled exception of type 'System.InvalidOperationException' in   System.Data.dll

     

Additional information: ExecuteNonQuery requires the command to have   a transaction when the connection assigned to it is in a   pending local transaction. The property has not been initialized   Transaction of the command.

I really have no idea how to solve it, because I'm new in this transaction. If anyone can help me I would be very grateful

CODE: Transaction Class

using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Data; using System.Data.SqlClient; using System.Data; using System.Data.SqlClient;

namespace CapaDatos { public class Transaccion { DataManager dataManager = new DataManager(); SqlDataReader leer; SqlCommand comando = new SqlCommand(); DataTable tabla = new DataTable();

    public void RegistrarPedido(string descripcion, int idCliente, string 
    idRepartidor, double montoTotal)
    {
        comando.Connection = dataManager.AbrirConexion();
        dataManager.BeginTransaction();
        comando.CommandText = "INSERT INTO PEDIDOSCLIENTES VALUES ('" +  
        descripcion + "','" + idCliente + "','" + idRepartidor + "','" + 
        montoTotal + "')";
        comando.ExecuteNonQuery();
        dataManager.Commit();
    } }

CODE: DataManager Class

using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Data; using System.Data.SqlClient;

namespace CapaDatos { public class DataManager { SqlConnection Conexion = new SqlConnection(@"Data Source=TOSHIBA\SQLEXPRESS;Initial Catalog=baseDeDatosPedidos;Integrated Security=True"); SqlTransaction Transaccion;

    public SqlConnection AbrirConexion()
    {
        if (Conexion.State == ConnectionState.Closed)
            Conexion.Open();
        return Conexion;
    }
    public SqlConnection CerrarConexion()
    {
        if (Conexion.State == ConnectionState.Open)
            Conexion.Close();
        return Conexion;
    }

    public void Commit()
    {
        if (Transaccion != null)
            Transaccion.Commit();
    }

    public void BeginTransaction()
    {
        if (Conexion.State == ConnectionState.Open)
            Transaccion = Conexion.BeginTransaction();
    }
    public void Rollback()
    {
        if (Transaccion != null)
            Transaccion.Rollback();
    }
} }