Step 1. Login you Envato account. In Download tab, find Hotel WP and choose the Installable WordPress Theme (the WordPress file).
Step 2. Login your server, then go to wp-content/ themes folder and backup your hotel-wp theme folder if you want or delete it. The content in your site will not be lost but if you have modified code, the changes will be lost. You have to reapply them after updating over.
Step 3. Exact new file hotel-wp.zip you have already downloaded from Themeforest.
Step 4. Drag & drop new theme folder hotel-wp to wp-content/ theme to override the existing files.