I follow the instructions:
"Upgrading a Theme
Download the latest zip file of your theme from ThemeForest.
Select to download Installable WordPress file only
Log into your WordPress site.
Go to Appearance > Themes.
Click the "Add new" button.
Click the "Upload Theme" button.
Select the zip file with the new theme version to install.
Select "Yes" from the "Upgrade existing theme?" option.
Click "Install Now"."
But I don't get the option "Upgrade existing theme", it just fails to install and I get the following message:
"Destination folder already exists. /home1/talkiny4/public_html/wp-content/themes/starter/
Theme install failed."