Installation via FTP is not supported, because most of Kimai's management tasks rely on the console.
The recommended way to install Kimai is via SSH.
If you don’t have the technical background for managing a server yourself and need to rely on a shared hosting package,
it is better to stop hosting business critical software yourself!
If you thought about switching to a managed server before (they are affordable these days)
you can contact me, I offer paid setup support