Typing in the Instant Search pane brings up search results based on any matching words in a message. If you want to search on specific parts of a message — for example, if you want to search based on who a message is from, you'll need to use advanced search terms.
To do this,
Click the Expand
button (as shown in the picture)
and, type the advanced criteria.
You'll notice that as you do this the words in the Instant Search
box are updated to show the new criteria.
Tip You can also type advanced search criteria directly into the Instant Search box. To get a feel for what to type, look in the Instant Search box when you use the fields in the expanded Instant Search pane.