Conditional Formatting in Excel

I have a Status field.  I am trying to automatically select an option based on the following:

• When E10 (Assigned To) is NOT blank AND F10 (Progress) is blank OR 0%, then K10 (Status) should equal "Assigned"
• When E10 (Assigned To) is blank AND F10 (Progress) is blank OR 0%, K10 (Status) should equal "Unassigned"
• When F10 (Progress) is greater than 0%, K10 (Status) should equal "Working"
• When F10 (Progress is less than 75% AND J10 (Days Remaining) is <= 5, then K10 (Status) should equal "At Risk"
• When F10 (Progress) is less than 75% AND J10 (Days Remaining) is 0, then K10 (Status) should equal "Behind Schedule"
• When F10 (Progress) is equal to 100%, then K10 (Status) should equal "Complete"

I keep trying to write IF statements but the values are not being selected.  Can someone please advise?