Yes, you need to install the homebrew channel via the exploit you want to use. Smash stack is the most widely used, but the others are fine ways of doing it as well. Then it's just a case of putting the
nintendont app on your SD card. For the exploit to work, you need an SD card 2 GB or less. No SDHC or SDXC, has to be SD. After installing homebrew channel, you can use any SD card you like.
You don't need any cIOS mods for
Nintendont, but if you want to use any USB loader, you absolutely have to.