Check out these two threads first if you haven’t already:
There’s lots of good discussion in there.
The short answer is: if there is nothing to test, no roll. No secret / no trap = no roll
Yes, the players always need to describe how they do something. How they do something makes all the difference in the world. If, for example, they correctly ferret out discovering the trap from your GM description and use some gear, like a 10’ pole, to detect it, you can say, “Good idea! You’ve found the trap.” (no roll) But, now they need to disarm it with Dungeoneer.
Or if there isn’t a trap, you could say, “Yeah, you poke around the floor, but there is nothing there save for the cold stone. You’re certain there are no traps in the chamber.”
Don’t worry about parties “searching too much.” It is not really a problem in the game. All it takes is one failed search to set off a series of twists that burns through torch light. If it does become an issue for you, give them some twists, grind them down, and then they will learn that they need to be judicious in their actions.
However, I find parties don’t search enough. They are so cautious in trying to survive or focused on something else in the room that they miss a lot of secret doors, forget to trigger instincts, or wade right into traps.