In the starter/safer areas of the game, you might get an quest to go to the outskirts of town and try to find some scrap pieces of metal with a small reward and being allowed to keep some of that scrap for yourself. Then you might asked to go out a little further for something harder to find. And then a little further...until you've learned the system pretty well.
And it can be a mix of spawned and static scavenge locations. The spawned locations disappear after being picked clean (think like a pile of metal or wood or a small vehicle) and then respawn nearby after a while, so there are general areas you know are good to look for certain scrap. The static locations could be larger vehicles and buildings, which require a good bit longer to scavenge, but offer the possibility of finding multiple things and more complete items (instead of scrap metal, you get a steel door to use for your own housing or old weapons that can be repaired, etc). The time required to scavenge a building can be lowered if you have a team! Instead of scavenging for 10 minutes by yourself, 4 people can scavenge for 2.5 minutes while 1-2 others keep a lookout (if you're scavenging in a dangerous area) with the ability to stop scavenging immediately to deal with any threats. After the scavenge of a static location is finished, it will be set on a timer before it can be scavenged again...with the larger locations having longer timers.
I would like it so you don't have to wait for the entire scavenge action to complete. If you go to scavenge a building hoping to find something specific and get on your way, then you should be able to stop once you've found that (meaning you see what you're getting in real-time instead of waiting for the whole 10 minutes to find out what you got).
And lastly, it will can be skill-based. Think of it this way, the newb who just came to town and doesn't know much about the world isn't going to be know what he/she will be looking for for certain things. That comes with experience, plain and simple.