How to implement EDS signing documents on the server side?

Question

PHP

Good day!
There is a server on CentOS, and clients with Windows 7 (which have CryptoPro CSP installed).
It is necessary to implement the signing of documents and verification of signatures on the site.
I do not quite understand where to start? I look towards cryptcp , but how to store keys (keys of all users on the server in a specific folder)? And if you solve the problem with this option, then you will need to create a database where to write the user ID, his EDS key, file name, right? And from the server, access this database and perform operations, after which, in the same table, set "1" in the required field - the signature is completed.
I also found a plug-in for the browser: CryptoPro EDS Browser plug-in, but I haven't figured out how to connect them yet.
Maybe there is some more or less ready-made solution that will help me?
My first question, I understand that most likely I did something wrong. Sorry in advance!