There are two ways to upload any theme into the WordPress site: Admin panel and FTP. The most recommended way is uploading via Admin panel, however, sometimes there may be size limitation for files uploaded that is why this manual provides both ways:
Download a theme package file from ThemeForest. Unzip the package file on your computer - the theme package folder will be created.
Installing a WordPress theme is super easy via your Dashboard
Sign in to your admin panel in yourdomain.com/wp-admin
Find Appearance → Themes in the Dashboard
Click the button Add New (on top of the page) and go for the Upload option
Open the browse, then pick elessi-theme.zip in the downloaded Theme package from ThemeForest
Click Install Now button
First, you need to uncompress the WordPress theme ".zip" in the Theme package downloaded from Themeforest. But in Elessi Theme Package, we have unzipped them already into Elessi folder and each unzipped folder contains all necessary files to install the theme, include layouts, CSS and PHP files contained all theme code. Using the FTP to transfer the folder of this theme to the WordPress theme's root directory: /wp-content/themes.