Sales Commission Project

i working on sales commission project , cannot figure out next, appreciated! here have far.

using system;
using system.collections.generic;
using system.componentmodel;
using system.data;
using system.drawing;
using system.linq;
using system.text;
using system.threading.tasks;
using system.windows.forms;

namespace sales_commission
{
    public partial class frmsalescommission : form
    {
        public frmsalescommission()
        {
            initializecomponent();
        }
        // calculate commission sales agents
        private void btncalculate_click(object sender, eventargs e)
        {
            // declare variables
            string lastname;
            string firstname;
            decimal commission;


            // assign variables
            lastname = txtlastname.text;
            firstname = txtfirstname.text;
            commission = lblcommissiontotal.



            // if first , last name both empty 
            if (lastname == "" && firstname == "")
            {
                // display word commission
                lblcommission.text = "commission";

            }
            else
                // display commission + first name + last name
                lblcommission.text = ("gates"); 

            // if sales numeric check if sales negative
            // if sales not negative
            // calculate commission

            // display calculated commission
            // else sales negative message user
            // else sales not numeric message user

here more information.

specifications:  write application determines commission earned sales agents.  must verify sales amount entered indeed numeric.  if not, display message box appropriate error message, select text, , allow user re-enter data.  sales amount must numeric , must greater or equal 0. when valid numeric sales amount has been entered, calculate , display commission (10% commission). 

the application should accept sales agent’s first name , last name.  when calculation commission calculated, display label “commission first name last name” entered in textboxes.

if there no name entered, display word ‘commission’.

if either first or last name entered… display phrase ‘commission ****’ using either first or last name.

when both first , last name entered, display ‘commission bill gates’ bill first name , gates last name.  ~ first name , last name should work!!

consider logical tab sequence , data alignment.

the clear button should clear data (entered , calculated).  exit button should exit application.

set appropriate accept button , cancel button.  set appropriate access keys.

when first name, last name or sales amount value entered, clear calculated display areas.

use standard microsoft naming conventions controls.

include appropriate comments in code.

we won't homework you. that's responsibility. can specific programming problems, need ask precisely troubling you.

Visual Studio Languages  ,  .NET Framework  >  Visual C#