Outputting a breadcrumb trail infers that there is some kind of relationship between parent pages and children (or grandchildren) pages.
You have not described what that relationship is and how you store it.
It could be done in a database, here is a contrived example of how 2 pages might relate to each other in the db.
++++++ and example row +++++++++
id | 4
parent_id | 1
title | About us
url | about-us
++++++ another row +++++++++
id | 12
parent_id | 4
title | How to find us
url | find-us
That could be pulled out to give
<a href=/>Home</a> <a href=/about-us.php>About us</a> | <a href=/find-us.php>How to find us</a>
OR the relationship might be defined by files in folders.
And a similar url breadcrumb could be generated by using file reading functions as well as sstr_replace() and ucwords().
If you explain how you establish one page knows what its parent is, and someone will try and help you make a breadcrumb from that.
Until you do that we would be shooting in the dark, hence nobody can a helpful comment which addresses your particular situation.