Not an experienced user, just need to know this.
Search Conditional Formatting in the help - F1 Or see Conditional Formatting - LibreOffice Help and also the link at the bottom of that page.
 
      
    Not an experienced user, just need to know this.
Search Conditional Formatting in the help - F1 Or see Conditional Formatting - LibreOffice Help and also the link at the bottom of that page.