kernel – Cannot install virtual machine on VMware

I’ve installed VMware Workstation 16.1.2 Player (21-05-18), and I want to install a virtual machine of Windows 10 with it, but this happens when I click the finish button: Could not open/dev/-vmmon: No such file or directory. Please make sure that the kernel module ‘vmmon’ is loaded. I also get this message afterward: Failed to initialize monitor device.

There is a YouTube tutorial on this issue, here: https://youtu.be/nKPALgwyDG4, but I can’t get past the first step because the command vmware -v doesn’t work for me. I’ve tried other tutorials on the internet, like this one: VMWare 15 Error on Ubuntu 18.4 – Could not open /dev/vmmon: No such file or directory. I went through the process, but during the rebooting, I might’ve done it incorrectly because when I test the driver with mokutil --test-key VMWARE15.der, I get this: VMWARE15.der is not enrolled.

I’m using version 21.04 (Hirsute Hippo) of Ubuntu, and I’m a novice Ubuntu user.
Thanks.