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".
- Click "Upload theme" button.
- 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: precia-1, precia-2, precia-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The uploaded theme appears in the Unpublished themes section.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 Your current published theme will become unpublished.