To Answer your questions:

1.I dont know where to get the codes

Like earlyer said, the JJ2 source code is not aviable... (i think its completly lost)

2.i dont know HOW to get them

^^

3.How do i make it a JJ2 prog for jj2?

Never written programms in C++ / Visual C++, but in Delphi i normally have the same WinAPI Calls, so google for:
- ReadProcessMemory, WriteProzessMemory, CreateRemoteThread, VirtualAllocEx,.....

4 and wth does Attach to Proccess mean?

If you want to read/write memory out/in an other process you need to get the PID (processID), there are about some api calls too to get it (FindWindow (/...) --> GetWindowThreadProcessId --> OpenProcess (this returns the PID in the end, this is everytime needed when you want to access JJ2's Memory), just google a bit).

5.where do I go to look to find all this stuff for jj2?

The "List of Jazz Jackrabbit 2 Memory Addresses" was sent earlyer, so with this and a bit googleing you should not have problems now

Wish you a lot of fun and don't gve up, but first lern the language where you want to write your programms in (if you are good it takes about 1 Month to lern and use the basics)...

Sfaizst