One of the most common concern on why new players are stuck in the tutorial is they are skipping on some details of the tutorial. One of which and most common is the Brave Burst.
Brave Frontier has a skill feature which is called the Brave Burst. A unit can only execute or unleashed a Brave Burst skill if the Brave Burst Gauge (BB Gauge) is already full. So how to do Brave Burst? See image below for reference.
If you are stuck in the tutorial for some other reason then please do send us a message via our Game Support page so we can help you out. If you do not know how to send us a message then please do read this article.