By default, the Find dialog assumes you want to search only in the translation text. To find using both source and translated text instead, click on the Both Source Text and Translated Text option at the top as shown above.
You can type your search text into the visible text boxes. The search texts do not have to be entire words, but each can be any part of a word.
This find mode works in what is called an "And" relationship. This means that Adapt It has to find both the source text entry and the translation text entry in the same pile to consider the result a match. If Adapt It finds the source text with some other translation, it moves on to try to find the combination somewhere else.
The default mode of search is case-sensitive meaning that that Adapt It treats "A" as a different character than "a". You can have Adapt It ignore the differences by checking the Ignore Case 
check box.
Adapt It assumes you want to search the lines without punctuation. If you wish to search the line with punctuation, check the Search in lines which retain punctuation 
check box. Adapt It then searches the line with punctuation. This feature is useful if you need to find a particular punctuation mark.
At times you may want to find a particular combination of words phrase, but you have not made them into a phrase. In this case, you need to have Adapt It, search for the words using multiple piles, not just one. To do this check the Allow the search to occur in text spanning multiple piles 
check box. This feature may be useful if you do want to convert the word combination into a phrase.
When you are ready, click Find Next to have Adapt It perform the search.