Alert does not mean you always get to go first.
The bad guy, who you were unaware of, acts on his own Turn. You don't magically get to go before he has gone.
However, Alert DOES mean you are not Surprised. This means you can use Reactions.
So, in my Seven Swords of Sin game on Sunday, the evil (& Hasted) Vivisectionist Wizard acted on his turn, blinded the party Barbarian who had just entered his laboratory, then stepped past him out into the corridor, cast Fireball... and had it Counterspelled by the party Wizard, who had Alert feat.
He didn't last too long after that; the party took great pleasure in poking him to death. The party wizard saved her group from a lot of hurt, and it didn't require having the Alert feat grant her magical superpowers.
The bad guy, who you were unaware of, acts on his own Turn. You don't magically get to go before he has gone.
However, Alert DOES mean you are not Surprised. This means you can use Reactions.
So, in my Seven Swords of Sin game on Sunday, the evil (& Hasted) Vivisectionist Wizard acted on his turn, blinded the party Barbarian who had just entered his laboratory, then stepped past him out into the corridor, cast Fireball... and had it Counterspelled by the party Wizard, who had Alert feat.
He didn't last too long after that; the party took great pleasure in poking him to death. The party wizard saved her group from a lot of hurt, and it didn't require having the Alert feat grant her magical superpowers.