I really need information about smb3, how it works, how to run file shares on the server thanks to this protocol, is there any information on testing, etc.

A fairly well-known protocol, but not free. You can still use it for free for testing, but you can't use it for private use for free.

Well, in terms of speed, is this network protocol very fast? It is very important to us that the data is transferred over the network protocol very fast. So that there are no delays and collisions during data transfer.

I've only read a couple of times about testing the SMB3 network protocol, since when you start the server on Windows Server, it comes in the installer package.  You'll have to pay a little for this network protocol in the new version. But you can also get it for free. Here everything is written about smb3, this network protocol is not so simple. But it allows you to increase the performance of working with files on a virtual machine or server.