OCMOD is a best way for modification in Opencart, that allows to modify the core file of OpenCart without touching the core files, we just upload a compressed file ***.ocmod.zip that contains install.xml and upload/ folder.
Flow of OCMOD code:
https://youtu.be/NCtiqTyEoUA?t=84
How to create the install.xml file for OCMOD?
https://youtu.be/NCtiqTyEoUA?t=416
How to create a zip file for extension installer in Opencart?
https://youtu.be/NCtiqTyEoUA?t=573
How to upload the ocmod.zip file?
https://youtu.be/NCtiqTyEoUA?t=1276
Steps for making changes to the core files of OpenCart
https://youtu.be/NCtiqTyEoUA?t=780
Testing Tips for developers
https://youtu.be/NCtiqTyEoUA?t=1548
