I will start off by saying I know nothing about this game basically. A friend suggested that I would enjoy it because of other games I have played in the past and I watched a few videos which seemed interesting so I got a founder’s pack and here we are.
So the question is, as someone completely new to the game what should I do first?
As someone new as well: Start it, click whatever you like clicking and play. This is just a beta. Don’t stress it, enjoy it without planing anything… see if you like it.
Create a character and do what you want to. if you wanna run around and gather stuff or find collectibles. do it. 1. its beta 2. you need to have fun and only you can decide whats fun for you 
Pick the best looking class for your playstyle (all viable) and get stuck in. I’d say do a couple of side quests if you fancy, but if you’re not bothered then just follow the main story. This is the fastest way to level up and unlock more of your class abilities. If you don’t love it (or even if you do!), try a different class. This will allow you to use beta as a test for what you want to play / invest your time into on the real release, where you can go full completionist and do every sidequest!
As others have said, just explore, enjoy, and relax 
If you prefer to have a bit more knowledge going into it, check out the links in this topic:
My advice is to use any downtime you’d like to watch videos from people who have been playing the game for months/years in Russia, Korea or Japan.
https://www.youtube.com/c/HiImFox and https://www.youtube.com/channel/UCWajiTYyiwalcfbJO-bDVpQ are the good ones I’ve found so far.
From there figure out the class that suits you and play. Everything you might want to know is online already either in video, stream or website form.
Good luck!