I was in your shoes before and you need to know that there isn't shortcut... you will lose A LOT! I would advice you to not waste time watching how other people play on youtube (they already know how cards work) and instead build your deck (anything you think it will work it doesn't matter if it is bad) and play, play, play... until you get to know how other faction archetypes works. You will need couple of days for this, depending how long you play daily. Eventually, you can try to make some net-deck and try it out (if you have enough resources for all the cards) but i would leave that for later, when you know how most of the factions (and cards) works. You can check this:
https://gwentup.com/decks
https://teamaretuza.com/academy/
About bread/wine icon:
It's card's provision (new way to balance decks and leaders). Provision system caps the total power of a deck. So, all decks now have a base recruit cap of 150 and each leader adds its own value to increase that cap. A leader value of 15 + base deck cap of 150 = recruit cap of 165 for your deck ( you will see this in deck-builder menu).
Image bellow, example of leaders value (ignore last 4 cards on bottom of the image).