If you want to modify the static parts of the breadcrumb display (that is, not the links), it’s very simple to do.
Open up the functions.php file in your child theme and add the following code. The code should be entered at the end of the file, just before the closing ?> if there is one.
Default Options for Breadcrumb Template
As these are the default options, you can edit the ones you want to change, and delete the other lines starting with $args. For example, if we wanted the separator to be a → symbol (a right arrow with character code →), the home value to be Start and the author pages to have a label like Entries written by then you’d just need the following: