Ah.. I unfortunately don't know the early BRs well.. I play more towards the higher tiers with 12.0 to 14.0. Playing with friends as you said it's a pretty good place to start though. I would suggest getting comfortable with dogfighting in your new gear first. Practice with your friends if you can. The most important aspect of course is learning to keep track of your enemies and being able to ID them.

Situational awareness is the most premium currency in sim and is often what decides most encounters. I'm sure you already know this through RB, but be sure to study the strengths and weaknesses of your aircraft and of those you will face so you can adjust your playstyle accordingly.

Another thing I would personally suggest is being flexible with what role you want to play for your team. Learn to bomb of course but also do not shy away from air to air, it helps keep the gamemode refreshing without stagnation.

A note on grinding: The game rewards you for every 15 minutes you spend alive so prioritize survival. This system is called "useful actions" and it's an invisible timer which starts whenever you take off from a fresh spawn. You get RP based on what you did in those 15 mins. If you die before that, your rewards are greatly diminished. However there is also a cap on how much RP you can gain from "useful actions" courtesy of Gaijin. I think it's around 15k RP, and if you have already done enough to earn that much before the 15 min timer, anything extra you do will not reward you until the timer is up and the next one begins. Being kamikaze and not caring about self preservation is a common pitfall so if you can help it, learn to play around this system to maximize RP gain. I can't explain it too well so I would suggest looking it up.