Need help with a flowchart

I need help with a flowchart in a question I'm doing. I've completed the programming code but just have no idea on flowcharts if anyone can give me an idea on how to do this then I'll appreciate it. This is the question:

Write a C++ program that reads from keyboard 3 integers, with proper input prompt, and then displays the maximum sum of any pair of numbers from these three. If the 3 numbers are 5, 6 and 7 for instance, then the maximum sum comes from 6+7=13. Draw the flowchart of this C++ program, and also desk check the program for the three input integers 12, 3 and 7, or a different set of 3 numbers which will make the desk checking less trivial within your program design.

I've completed the code which is:

Code:

#include <iostream>
using namespace std;

int main()
{
    int num1, num2, num3, sum;
    
    cout << "Enter number ";
    cin >> num1;
    
    cout << "Enter number ";
    cin >> num2;
    
    cout << "Enter number ";
    cin >> num3;
    
   /* if(num1 >= num2)
    {
            
            
    }*/
    
    if(num1 > num2 && num3 >
     num2)
    {
            sum = num1 +  num3; 
            cout << "The sum of " << num1 << " and " << num3 << " = " << sum << endl;
    }
    else if(num1 >= num3 && num2 >= num3)
    {
         sum = num1 + num2;         
         cout << "The sum of " << num1 << " and " << num2 << " = " << sum << endl; 
    }
    else if (num2 >= num1 && num3 >= num1)
   {
        sum = num2 + num3; 
        cout << "The sum of " << num2 << " and " << num3 << " = " << sum << endl;
    } 
  //else
  //{
    //  cout << "all three numbers must be diffrent" <<endl;
     // }
     
     system("PAUSE");
     
     return 0;