How can I create and use a self-signed certificate for my TrueNAS Core server?

[Mannekino]

I've been fiddling for a while now to get the self-signed certificate working for my TrueNAS core server that will be accepted by my browser (Chrome). I've tried creating it two times now with also creating a CA inside the TrueNAS Core web UI but nothing seems to be working. I've exported both the CA and certificate .crt files and tried importing them into the Windows 10 certificates using the MMC snap-in but it doesn't get accepted.

Both the manual for FreeNAS 11.3-U5 and the new Docs portal are no help at all. Is there any guide out there to get this working? When I export the certificatie it doesn't show a certificate chain. I've also tried the method of creating a CSR and then signing it by the CA I've created and then exporting the newly signed certificate but that doesn't work either.

I'm not sure how to configure all the settings for both the CA and certificate itself. This is just something nice to have to can use HTTPS for my TrueNAS Core server internally.