Baldur's Gate 3 features turned-based combat, and similar to most RPGs set in the same sub-genre, there are multiple commands and tools to approach the combat and prepare yourself for the battle before the engagement occurs.
Using Stealth mode is not mandatory for players, but in difficult battles within complex maps, Stealth mode can help you a lot to position each member of your squad in a certain location before the engagement, so that you can use the environmental benefits during the battle.
How To Use Stealth Mode
Every character in Baldur's Gate 3 has the ability to go into Stealth mode no matter whether you are exploring the world or are in the midst of combat. In order to activate the Stealth mode, you need to click on the "Hide" command for every character.
As soon as a character enters Stealth mode outside of combat, the area that can be observed by enemies will be highlighted in red. If the NPCs that you are trying to hide from are hostiles, you will trigger combat mode as soon as you step into the red zone, even while using.
However, if you stay in an area that is not highlighted, you will remain unspotted. This will allow you to sneak around hostile NPCs and continue your exploration. Also, it could help you to send each character to a different location in an area to target your enemies from multiple directions when the battle begins.
Other than that, Stealth mode will allow you to surprise your enemies from behind and perform any kind of attack on them before the engagement begins. In this case, the attacking character will retain their Action Point as soon as the battle begins, which is more like two consecutive attacks with a single character.
In Stealth mode, the player makes almost no noise, and as long as you are visually hidden, you can rest assured that no one can spot you. We strongly suggest you ungroup all your companions in Stealth mode and move them around the enemies one by one. Moving in a group in Stealth mode could be a bit dangerous as some companions may end up inside the red zone unintentionally.
When it comes to using the Stealth mode during a battle, you will still see those red highlighted areas, but even hiding in safe areas will now depend on your luck. If you are lucky, a prompt will appear above the character's head saying "Hiding Successful." In this case, when a hostile NPC gets close enough, they can't see or attack your character as they will remain hidden for a single turn. However, if you get a "Hiding Failed" message, you will remain spottable for all hostile characters. Usually, you are suggested to use the "Hide" command during combat as your final Bonus Action Point in directing a character.
Keep in mind that attacking any objects while you are in Stealth mode will alert the hostiles even if you are outside the red zone.