You are correct on the locked container but there's more. This is in layman's terms to keep it simple.

It has to be in a trunk or out of reach of the driver which generally means the back of the vehicle.

A locked container can be as simple as a backpack with a little lock on it. That's how I transported mine back in the day.

Ammo must be "in a separate container" which means magazines are not touching the gun. A pistol rug with a pocket counts. Basically means the gun isn't loaded at all.

I think that sums it up. That info is 5 years old but I'm pretty sure things haven't changed in that area.