Step 1 Copy all the required files to the following directories

admin/controller/extension/module/onwebchat.php → "opencart folder"/admin/controller/extension/module
admin/language/en-gb/extension/module/onwebchat.php → "opencart folder"/admin/language/"language you are using"/extension/module/
admin/view/template/extension/module/onwebchat.tpl → "opencart folder"/admin/view/template/extension/module/

catalog/controller/extension/module/onwebchat.php → "opecart folder"/catalog/controller/extension/module/
catalog/view/theme/default/template/extension/module/onwebchat.tpl → "opencart folder"/catalog/view/theme/"theme you are using"/template/extension/module/
catalog/language/en-gb/extension/module/onwebchat.php → "opecart folder"/catalog/language/extension/module/

Step 2 From OpenCart admin panel, choose Extensions → Extensions. From dropdown select Modules, find onWebChat - Live Chat and click the Install icon. Click the Edit icon to configure the module with your Chat Id and Save.

If you don't have an onWebChat Chat Id, please create an account here.

Step 3 Navigate to the Design → Layouts section of your admin panel to configure onWebChat Live Chat in the layouts you prefer (e.g. Home, categories, products,etc). Click the Edit icon of the layout, in Content Bottom click the add button and select onWebChat - Live Chat

Step 4 Go to 'Design' → 'Layouts' section to set the appearance of live chat widget on your website layouts. (ex. Home, categories, products..). You should do it for all layouts in order to show the live chat widget on all your webpages. Click on "edit" icon of layout.

Step 5 Click on "+" button. Then click on "edit" and select "onWebChat - Live Chat" from Content Bottom. Final click on "save" button.

Once you have saved your changes, you should see onWebChat - Live Chat widget on your OpenCart store.