Installing Semplice takes two minutes, tops. You simply install it as a theme in WordPress.
How to install Semplice
From the Wordpress admin dashboard, navigate to Appearance > Themes. Now click the 'Add New' button.
Next, click the 'Upload Theme' button, then upload the theme file and activate it. Semplice will automatically launch.
Note: In the zip file you received from Semplice, there's another zip file. Be sure to upload that second zip file, not the first. Otherwise you will get a 'error: missing stylesheet' message.
And you're done! Did you do it in less than two minutes? Congrats! 🏆
'Package could not be installed, missing stylesheet' error
This happens if you are uploading the wrong zip file. Unpack that zip file and upload the second zip file inside. That zip should be called either semplice4_single.zip or semplice4_studio.zip depending on your license type.
'Destination Folder Already Exists' error
This can happen if there was a previous install of Semplice 4, or you are trying to upload Semplice when it is already installed. If you are upgrading from a Single to Studio license, it is not necessary to re-install Semplice. Rather, you can input your new Studio license under Semplice > Settings to unlock Studio features.
In some rare cases, the Semplice folder will remain in WordPress while Semplice is not actually installed. To resolve this, either use an FTP client (or a handy plugin such as this) to navigate to your theme folders, and either delete or rename the 'semplice4' folder.