When I try to upload the theme, I get this message
The uploaded file exceeds the upload_max_filesize directive in php.ini.
Attached files: error message.jpg
Before we get to the filesize issue, please try the following:
Unzip this file, you downloaded. There should be a smaller dentalia.zip file inside. This is the theme file. Try to upload it again to the WordPress the same way you uploaded this one. This will most probably resolve the issue and let you install the theme normally.
Now let's get to the error you are seeing.This error is saying that upload filesize directive is set too restrictively on your server.
You can change this in your php.ini file on the server, or contact your hosting provider to change it for you (Not all hosting providers allow access to php.ini file). The reason why you should change the upload size settings is not only because of the theme installation, but because you will get the same error when you will try to upload larger images, videos or documents to your WordPress.
While you are at configuring the php.ini settings, here are a few other recommended settings:
max_execution_time 600memory_limit 256Mpost_max_size 32Mupload_max_filesize 32M
The reason hosting providers limit those is because they host a lot of websites on the same server and they don't want each to spend too much resources. In practice however, a website resource usage is not constant, mostly it is pretty low, but it has peaks. It needs these resources occasionally, because some processes are more resource consuming, like for example processes like content import, WordPress updating, batch resizing images, creating backups... So to avoid any issues, we strongly recommend lifting those restrictions.
I hope this helps,Andrej