The Sundanese script has only been recently included in the Unicode standards, but now you can indeed type contempoarary Sundanese script. Historically, there are other forms and standards and styles and whole other scripts for the Sundanese, but I know even less about those. Read the history at Kairaga.com
To actually see the script (at least Aksara Sunda Baku, the new, consensus, modernized one) on your screen, you’ll need the right font installed, which took me a couple of tries.
- Sundanese-unicode-2-0-ttf as mentioned in the comments at Kairaga,
- Automatic transcription (missing the letter F, maybe others?)
- Wikipedia’s Sundanese info
Now read the Sundanese wikipedia article.
If I’ve understood the wikipedia page correctly (and I translated it from Sundanese, which I do not speak, so that’s not guaranteed) it’s like Thai and some other Brahmi-derived scripts in that there are primary consonants that a decorated with modifies to change the succeeding vowel. This is, if I am not mistaken, termed an abugida system. So the following should say “Lotekno”; But without the modifiers it would say La-Ta-Ka-Na.