Linker Error C++ "undefined reference "

Trying to compile my program via g++ -o prog1 main.cpp -std=c++0x

I get the error:

/tmp/cc1pZ8OM.o: In function `main':
main.cpp:(.text+0x148): undefined reference to `Hash::insert(int, char)'
collect2: error: ld returned 1 exit status

main.cpp

#include 
#include 
#include 
#include 
#include 
#include "Hash.h"

using namespace std;

int main(int argc, char *argv[]) {

//preset prime number 
int prime = 101;
hash h1;
int key;
Hash HashTable;

// check for Request & string parameters
if(argc != 3) {
    cout << "Run program with 2 parameters. [Lower Case]" << endl;
    cout << "[1] insert, find, or delete" << endl;

    cout << "[2] string" << endl;
}

if(strcmp(argv[1], "insert") == 0) {
    //Get Hash for argv[2] aka value
    key = h1(*argv[2]);

    //check 1
    cout << "Hash: " << key << endl;


    key = key % prime;

    //check 2
    cout << "Mod 101 Hash: " << key << endl;

    HashTable.insert(key, *argv[2]); //PROBLEM here

}

return 0;

}

Hash.h file:

#include 
#include 
#include "LinkedList.h"
using namespace std;


class Hash {
//100 slot array for hash function
LinkedList *hashFN[100];

public:
void insert(int key, char value);
//void deleteItem(int key);
//char* find(int key);



};

Any ideas? Using this to build a hash table with set size.

Edit: Hash.cpp file

#include 
#include 
#include "Hash.h"


using namespace std;

void Hash::insert(int key, char value){
*hashFN[key]->addFront(value);
cout << "Success!" << endl;

}

Trying to compile via terminal now with:

g++ -c Hash.cpp -o Hash.o

g++ -o prog1 main.cpp Hash.o -std=c++0x

It goes into an infinite loop somehow.