Ok, to run preloader:

1. Download preloader
   
2. Open your SD card on your PC and go into the "apps" folder, if this does not exist then create it now
   
3. In the "apps" folder, create a folder called "preloader"
   
4. Put the "preloaderv0.29-jodi.dol" file into the preloader folder and name it "boot.dol"
   
5. Put the hacks.ini file on the root of your SD card.
   
6. Load the homebrew channel and launch preloader, this should install preloader for you
   

Preloader will now start whenever you turn your Wii on. You can change this so it autoboots the homebrew channel or your system menu if you don't want to see preloader every time you boot up your wii.

Check out the system menu hacks, you probably want to turn on all region free hacks and of course your update blocker. Save your settings then you should be good to go.

Make sure that you can launch the HBC from within prelaoder because this is a great way of recovering from any problems you may get with your Wii. If the HBC does not launch from preloader, you will need to update your HBC. Do this in the same way you installed preloader using the hackmii installer instead and of course a "hackmii" folder in the "apps" folder on your sd card.

If you want to upgrade your neogamma, I would suggest that you delete the channel you have already and install a Neogamma forwarder channel then install a neogamma.dol into your apps folder (so you can see it in the HBC). This is a much better option than using a fully fledged channel as you get features like online updates that are otherwise impossible.