In OpenCart 22.214.171.124 creating a custom theme is little complex .
To start with copy the default folder found in upload/catalog/view/theme/default to a new folder in the same directory. Name it “mytheme“.
Then copy the theme_default.php file in upload/admin/controller/extension/theme and place it in same directory. Name it “mytheme.php“.
- Rename the class to (line 2):
ControllerExtensionThemeMyTheme + Replace all “theme_default” text to “mytheme“. Yes there are a lot (197).
Copy the theme_default.tpl in upload/admin/view/template/extension/theme and place it in the same directory. Name it “mytheme.tpl“.
- Replace all “theme_default” text to “mytheme“. (48)
Copy theme_default.php in upload/admin/language/en-gb/extension/theme and place it in the same directory. Name it “mytheme.php“.
- Set the new theme’s title in heading_title (line 3) to “My Theme”.
Finally for the thumnail image to show correctly in store settings rename default.png to mytheme.png in upload/catalog/view/theme/mytheme/image Now go into your Administration > Extensions > Extensions and select Themes in “Choose the extension type”. You should be seeing your new theme. Install it with the green (+) button and edit it to enable it. Also ensure you set the correct theme directory whilst editing the theme!
Then in System > Settings edit your store to use your new theme.
That should do it. You can now go ahead and start chopping and changing the default theme
Alternatively you can visit here ::
finally i found this doc here which helped me a lot http://undefined.gr/site/2016/10/09/custom-opencart-2-3-0-2-theme/