The transliteration feature works as follows: When transliteration is enabled, the texts you typed in text field will be automatically translated into Nepali after you hit "Space Bar". :
The transliteration will attempt to match the sounds of the letters as accurately as possible between the two alphabets. However, if you find that it is incorrect, you can fix it. When you find a word you want to change, just click on it once, using the left mouse button. As illustrated below, this displays a short menu of alternate spellings, as well as an option to switch back to the original.