Generally, that message is referring to expenses for which you entered a description but have no amount entered.

Click on Forms in the upper right corner, then scroll to your Schedule C, or worksheet that has a red exclamation point beside it in the list of Forms in your return.

Click on the Errors icon at the top of the Forms list.  At the bottom of your Schedule C, you will see the first error, click on the down arrow and it will take you to the error.  (See the screenshot below)