BB has a few key mechanics that I'll go over to help the youngin's (weaklings)
Important mechanics -
1. Blocking: If you hold back or down back you will block and not take damage from your opponents attacks. Trust me blocking is good.
2. Instant Blocking (IB): If you press back or down back at a specific timing to a certain attack your character will flash white and allow your character to recover 5 frames faster or 10 frames faster if you IB an attack in the air. IBing has some pretty sweet uses, it allows you to punish the infamous Jin, ice car spam and Ragna's Hell's.... (the first part)
3. Barrier Guard (back + A+ B): You flash green and drain from your "Barrier Gauge" honestly, the gauge is useless it is super rare that it actually runs out. Barrier guarding lets you block CERTAIN moves that are considered air unblockable, like Ragna's 6A. Be wary though, Barrier guard adds more blockstun to your character, but you also gain the advantage of added push back while blocking.
4. Counter Assault "Dead Angle" (While blocking, Forward + A + B ): It costs 50 meter and can only be done while you are blocking. Basically it's a DP that is done while you are in block stun and is a great way to get your opponent off of you if you are afraid of blocking or damn lazy like me. Some characters do not actually do an attack, Hakumen (does 6d) Noel (does some ghetto slide through thing) Tao (Flies to outer space) Arakune does his grab.
5. Burst (MASH ALL THEM BUTTONS): A burst requires one stock (you start the match off with one and gain one more if you lose a round) The burst can be used offensively and defensively. Offensive burst is gold and sends your opponent spinning into the air and allows you to combo. Defensive burst is done while in block stun or getting hit. This burst just knocks your opponent away, it has its uses. *bursting halves your primers rounded down 5 primers goes to 3 and 4 will go to 2
6. Guard Primer(You blocked too good and now you get punished for it): Certain moves in BB remove "guard primers" If you lose all of your guard primers you are guard crushed for and your opponent gets a free combo. If you are guard crushed in the air you get wall bounced. *You can barrier guard the last guard primer (but this consumes 1/3 of your barrier meter), thus letting you not get guard crushed