Trouble figuring out what to do

[Tarious]

If I could get help on understanding what and how I should do things that would be great.
Implement and test a C++ program that, assuming that you have character arrays that are of size N (locations 0 through N­1):
Reads a series of strings of the form "aactgcta..." from a file into a character array called original (the string will be less than N in length)
Change each of the characters in original to be uppercase versions of themselves
Copy the contents of original to a character array called duplicate
Reverse the contents of duplicate to a character array called reverse
Compliment (A ­> T, T ­> A, G ­> C, C ­> G) the contents of reverse to a character array called reverseCompliment
Display "original = aactgcgccgta..., reverse = ..., reverse compliment = ..." for each entry in the file
For the purposes of this lab N <= 10.
My code so far;

#include <iostream>
#include <fstream>
using namespace std;

int main(){
    ifstream inputFile;
    const int N = 10;
    char duplicate[N], reverse[N], compliment[N];
    
    inputFile.open("DNAreads.dat");
    char original[N];
    if (inputFile.is_open()) {
    }
    
    for (int i=0; i < N-1; i++){
        original[i] = toupper(original[i]);
        duplicate [i] = original[i];
    }
    
    for (int i = 0, j = N-1; i < j; i++, j--){
        reverse[i] = original[j];
        reverse[j] = original[i];
    }
    
    for (int i = 0; i < N-1; i++){
            if (reverse[i] = 'A', compliment[i] = 'T')
            else if (reverse[i] = 'T', compliment[i]= 'A')
            else if (reverse[i] = 'G', compliment[i]= 'C')
            else if (reverse[i] = 'C', compliment[i]= 'G')
                }
    cout << original, reverse, compliment;
    
    inputFile.close();
}