(it will search for the typed value in any field).
Unless a setting for that field in the Inspector does not permit a quick find to be performed on it.
Add your text field to your layout. Often it is very useful to give this field global storage so that the value remains visible after performing the quick find and so that criteria used by you for the quick find does not interfere with a quick find performed in the same manner by another user at the same time.
Add the script step to your script and then double click it or click the specify button at bottom right to open the specify calculation dialog.
Find your text field and add it to the specify calculation dialog as the sole term in the calculation. Click OK and you are done.