If you want to search data in the grid, press right mouse button and choose "Find…" in the popup menu or press button 
on the toolbar. In the dialog window select search options and click "OK".
If the substring is found, cursor will be moved there, otherwise you will get warning message. To repeat search, press F3 or select "Find again" from the popup menu. Note that the substring is searched in all fields.
You also can do the "Find and Replace" with Ctrl+R.
With its help you can find the text and replace it with needed one. After finding it, program will ask you for replacing confirmation.
See also: