Darkness: https://2e.aonprd.com/Spells.aspx?ID=59
Seek: https://2e.aonprd.com/Actions.aspx?ID=84
Spell Darkness is 20 ft Darkness. The player don't have the darkvision. I master roll 2d20, 1d20+TxC,1d20 11+ "see" the adversary, 10- doesn't see.
1) Is correct?
2) Player must seek the advesary... But 1d20 other... There are 3d20, TxC, 1d20, e 1d20+perception...a what serve the seek?