Download xampp and uncomment oracle 12c extension or 11c 'extension=oci8_11g' for xampp 7.2.9
Download instant client 32 bit and set its path
Download instant client 32 bit SDK package and set its path
Copy instant clients and SDK dll files to xamp\php\ext, xampp\php\ and xampp\appache\bin\
Download php-oci of same php version of tread safe x86 then copy its files to php\ext*.dll,
php version is written on top of phpinfo tab of xampp admin.
OCI8 will appear on phpadmin page or apache admin then phpadmin tab. It means phpOCI has been installed.