WP MultiSite setup using subdomains

So I've been working with WordPress for a while and have done all kinds of things, ALL except setting up a MultiSite. So here I am :slight_smile:

I need to create a MultiSite WP. It would be in the ROOT, but I would be using subdomains for different sections of the website (same look as the website. I would like it to be seemless). So I need some good advise/easy-to-follow tutorials/must-have-plugins:

1. Setting up MultiSite WP
2. Setting up the subdomains (I'd be using Plesk. I know how to set them up, but where would they point to? a sub directory, root, etc.)
3. What plugins would I need to make this work smoothly for me?

Thanks in advance!