You aren't allowed to load unsigned drivers on modern 64-bit Windows systems, or 32-bit systems with Secure Boot turned on. If the sample driver is not signed, it generally makes sense to figure out the way it is being executed in the wild (for example, by abusing other legitimate drivers) and reproduce it. In this way, we can guarantee that malware will behave exactly as expected.
Alternatively, it is possible to disable system security mechanisms. The most reliable way to temporarily disable it is by going to the advanced options for the booting process and selecting the Disable driver signature enforcement option. Additionally, make sure that Secure Boot is disabled in the firmware settings if present. Another approach that involves using the bcdedit.exe /set testsigning on command is not recommended for analysis as it still requires the driver to be correctly signed by some certificate.
Now, it is time to load the analyzed driver. This can also be done straight...