Hi,
I only have ONE server, which I intend to use as a master (at the moment I don't need to have a slave at all).
> Sir you can install KVM virtualizor on your server using this wiki >>https://www.virtualizor.com/docs/install/install-kvm
and in the future, if you want to add a slave server on his server then you can use the below wiki to add a server
>>https://www.virtualizor.com/docs/install/add-server
Can I use it as a KVM master server or do I need two servers (a master and a slave) to be able to use KVM?
>> There is no need for a slave server if you want to create VPS on the master server then you can install KVM Virtualizor on your server using the above wiki.
I want to be able to run Windows VPS servers there.
>> Yes you can run windows VPS on that server
Is there any particular good configuration that you recommend in order to allocate enough resources to a Windows or Linux VPS?
>> Sir, there is no specific configuration recommended in order to create windows or Linux VPS, it depends on your usage you can allocate resources to the VPS in accordance with that.