[REQUEST] New to battling, need some help please!

[Civilpsycho]

Hello or should I say Alola. I'm new to online/comp battling but I would love to get into it. Yet there is an impossible to miss mountain in front of me, between natures, IV EV and what Pokemon are good for what roles (and what roles I should have in a team) I'm lost. So this is a simple cry for help from the players more accustomed to the ways of comp. any and all help is welcome. I currently have a short list of my current favourites in Alola and I think that would be the best place to start. 
My current short list is 
Salazzle 
toxapex
Vikavolt
Tsareena
Beware
Lurantis
Marowak (Alola form)
Muk (Alola form)
Golisopod
Lycanroc (midnight form)
Mimikyu
Araquanid
Palossand 

To make it clear I'm playing Pokemon moon, and I'm not looking to go to any major tournament or any thing like that, I'd just like to make a decent battle ready team.