I cant load Hdd plugins on my usb PLEASE HELP

Hi,
I paid for a Stealth server i wanted to try out.
And i tried to load them over my usb(how i usually do with everything)
Then the seller is telling me its only working if i load them over my internal hdd…
So i dont have an internal hdd i have 4bg internal storage and external 1tb usb hdd
Does someone know how i can convert them or how i bring this to work without me having to buy an internal hdd?

Regards

Put them on your 4GB internal memory. That is basically your internal HDD.