Proliant DL20 gen9 4 sff Hot Plug bays with non Hot Plug?

We have a brand new "HPE ProLiant DL20 Gen9 Server". It came with 4 sff hot-plug bays but none HDs. And the user guide doesn't say we can plug any non-hot-plug HD. Is it possible?
In case it is not possible, what HP products can be pluged in this unit?

Thanks in advance and greetings