While sneaking your speed is halved as you try to move silently and unnoticed.
If you end your turn with
Partial Cover or
Full Cover you can try to
Hide to become
Hidden.
After each move you must be behind some kind of cover to remain
Hidden, or be
Invisible,
Greater Invisible, or
Obscured to remain
Hidden.
Each time you use a move type while
Sneaking, you must roll your
Sneak vs every
Enemy (or opposing creature team) within a 20ft sphere of the path you moved.
Unless otherwise stated you must be behind cover after the move is completed, or have effect that grants some type of visible obstruction, like
Invisible as stated above.