How does one activate the stealth/sneak skill?

[Stratagem]

Or is it passive?

We are also having problems with picking locks on doors.

Thanks for the help.

[dantivirus]

They are both passive, as to picking locks on doors, only some doors can be picked the others you will need to find the appropriate key for...sucks I know. Lock picking has very few uses in this game. Kinda kills the Thief class. All you do is mainly open chest...oh gee wow. :(