Explanation on how to configure RAID1 mirrored on TOS 5.1

[sim667]

Im trying to find some basic instructions on creating a basic RAID1 mirrored setup on TOS 5.1. I've got matching 4TB disks I'd like to mirror and partition into 2 volumes.

I can only find instructions for TOS4 which aren't applicable anymore, and I just don't understand the whole TRAID thing, which I suspect isn't applicable on TOS 5.1 either.

I'm not wanting to install TOS 6 as its beta.

Can I please be provided with suitable instructions for this?

As a guess I'm adding both drives to the same storage pool in TRAID configuration, and then I can create the two volumes on the pool, but I have no idea if that's correct.

[Gremlin]

Of course TRAID is available in TOS5.1.
When installing the OS you are offered options which default to the preferred choice for the system. But you don't have to accept those and can select your own options.