Whenever you write a description or story that contains spoken words, you must be careful to use correct punctuation in the speech. These are called speech or quotation marks, and the rules for using them are quite straightforward.
This is what you should do.
Enclose the actual words spoken inside speech marks. These are often single when printed and double when written by hand.
The important thing is to be consistent: 'I am feeling tired,' said Suzy, yawning.
'I am feeling tired,' said Suzy, yawning.
It is clear to the reader what Suzy says: Everything is inside the speech marks. A good way to remember this is to think of a cartoon. The words spoken by a character go inside a speech bubble. So just think of putting everything that would go inside a cartoon bubble within the speech marks.