Which partitions can I delete?

Hello everybody
I just bought a Nitrokeypc1 and unfortunately the initial onboard Qubes OS installation failed. So I downloaded QubesOS and made a USB installer. I succesfull installed Qubes but now under “USB” devices I have a 1GB “Samsung SSD 990 PRO 1TB” entry. Now I think this is a partition on the SSD drive I didn’t delete under the installation. When I look in the BIOS bootmanager I have both a “UEFI shell” and a “Ubuntu” partition. Do any of you know if I can delete the “Ubuntu” partition? and what about the “UEFI shell”?

Any input is highly appreciated. Thanks in advance.

Best regards