This step is entirely optional, but worth doing to save wasting a blank DVD if something went wrong.
It consists of 2 steps:
I'm not going to bother running through this in detail, since there are so many possibilities of software to use, and most are very user-friendly
For ISO compilation I use UltraISO, which you just need to drag the files you want into the ISO, change the volume label, and save.
For mounting, I use Daemon Tools (purely because it was first to have x64 support).
Using whatever tools you use, compile the ISO and mount it on the virtual drive. Now install from this virtual drive. Hopefully everything goes smoothly, but if for some reason it fails try running through the steps again. If you keep having trouble, you can contact me and perhaps I can help.