The steps to post a Win7 Disk Mgmt screenshot are the same. I copied that tutorial from my older Win7 tutorial for the same thing.
The Manual refers to UEFI, so right before reinstall you'd go into UEFI Setup via the key given on first screen to access UEFI Setup, change settings to UEFI enabled, CSM or Legacy BIOS disabled, Windows Boot Manager is set first to boot (or will invoke itself during install).
Then during the booted Custom install follow the steps closely in Clean Install Windows 10 to delete all partitions down to Unallocated Space and click Next to let it auto-create and -format needed partitions and begin. This makes it foolproof.
Your settings may vary a bit so read your Manual to fully understand the UEFI settings if there is any question.