S4048T-ON High Availability

Hi there, I have two of these switches that I want to run together in High availability mode. I'm guessing I would need to connect the two switches together via at least two of the additional six SFP interfaces and then configure the other 48 ports using the command line to mirror them on the other switch?

I've been reading up a little and the admin guide suggests the switches need to be stacked and "redundancy force-failover" be used. I don't think this is what I want. Is it VLT that I need?

I'm very new to the Dell CLI, so any pointers you can give me would be greatly appreciated. I guess what I want to do is as follows...

1. Reset the switches to default settings. These are 2018 models using OS9
2. Connect the switches via the SFP ports and configure those interfaces. How many  / which DAC cables do I need?
3. Configure each switch to run together via VLT? A guide on this would be great if someone could point me in the right direction?
4. It's going to be basic l2 switching for a ceph cluster - so anything I need to think about or configure for that?
5. Security. I don't know this OS very well. Do I need to do anything to secure the switches? Admin passwords etc?

Finally, once I've set these up, I will need to bond the interfaces on the servers. What's the recommended method for that - and if using "active active" am I essentially getting 20Gb/s here - doubling my bandwidth, or does it not work that way?

I'm very appreciative of any help you can throw in my direction.