How Do U Know When The Street That You Are On Is A One-way Street?

There's a sign at the entrance to it. If you didn't see the sign, you shouldn't be driving.

is the sign placed at the entrance to show you should not enter.  There are arrows facing in one direction - and the cars if any are parked/going in one direction

There also is no yellow lines. If all the lines are white you are on a one way street.