I just need my players to give me actions, not behavior. If they're in a room and want to search it, I don't need or want them where or how exactly they are searching.* Their characters, in-world, have more perfect information than I could provide to the players. If there's a hidden item in there, it has a DC to find it, and as long as the players tell me they are searching the room, I'm content to have them roll, I describe the result, and we keep the game moving.
IMXP, new players can get somewhat intimidated by the abundancy of choice in a TRPG, which manifests itself in two ways: 1) asking "Can I...?" questions, and 2) trying to engage with the game by pushing "buttons" on their character sheet. The first tends to resolve itself with experience, and seeing other players simply declare their actions. I also try to be encouraging by answering, "Yes!" as much as possible. For the second, I just explain to the player that they can just tell me what they want to do, and I'll determine if they need to roll or not. Then, I ask for rolls only if I think failure is meaningful. I find that eventually they pick up on that more often than not I'm not going to require a roll, and the initial impulse to engage with the game mechanically is replaced with natural adverseness to bringing probability into the interaction.
*Of course, in B/X there are no skills, and aside from traps and secret doors, no search rolls. In that case, I seek to break the searchable areas into manageable chunks. If I say there's a bed, and they say, "I search the bed," I assume they give a thorough search. I'm not going to hold out for the magic words, "I search under the bed," or even, "I cut the mattress open to look inside." A little more attention to detail is required than with 5e, because B/X foregrounds the exploration aspect, but I try to make those expectations clear to the players.