First of all, you will need TP (or the a homebrewchannel for launching the Twilight hack) to do what you are trying to do.
Second, you can get a .wad one of two ways. The easier is just to find the .wad online (it's not that hard). The harder of the ways is to dump your wii filesystem and build your own .wad, but I would go with the first option as it is much easier.
Thirdly, you are going to need all the .wad tools. Those being, a program to deconstruct a .wad, a program to reconstruct the .wad, a hex editor, and maybe a few more. There are guides floating around that will tell you what you need and where to find it.
However, all of this is really unnecessary since you can't use the twilight hack to install your custom wad.
ok so im not getting it with that tutorial they are telling you how to build a VC game when you already have the .wad file and rom of that exact game? what is the point then, if im not mistaken that just defeated the process and makes it absolutly pointless, I was thinking of making a rom into a VC of a game that currently isnt available on a .wad file but i guess thats just me,
That guide covers how to make a DVD from a wad file and how to insert a rom of a different game into an existng wad file. Like I said though its tricky to do.