After you have downloaded the package theme from Themeforest. Extract it on your computer then follow the below steps:

- Open your browser and log in to your admin page. Then go to "Online Store".

installation - step 1

- Click "Upload theme" button.

installation - step 2

- Then browse the folder you extracted theme package, enter the "theme files" folder. Choose a zip file corresponding theme style you want to install. Ex: shopcast-fashion-1, shopcast-fashion-2, shopcast-fashion-3,...

installation - step 3

- Click "Upload" button.

The uploaded theme appears in the Unpublished themes section. You can install a maximum of 20 themes in your store. To publish the theme on your online store, click Publish theme. Your current published theme will become unpublished.