Good job making your first 3d game! I imagine you spend a lot of effort!
As people already mentioned, it was really hard to select employees, but I also miss the multiple selection when you drag a frame like in the RTS games.
The camera is really sluggish, it would be more enjoyable to play if camera were responsive enough. But also, it was really unnecessary to make camera controls at all. It would be as good with a stationary camera, but placed at good location at the start (the initial location of the camera is placed very badly, because I didn't even see the workers at first).
I can also point out that base of design of this game is to apply workers to their jobs and just wait - it's not so good. It would be more engaging if player would do something all the time!
I also don't understand why everything is periodically on fire. But workers just fix everything automatically when it happens? To engage player to do something, you could do that player must put out the fire themselves by clicking on it or something. But now it's just "assign workers and wait".
Overall, I see you did a good job making this game! Hope you will make your job easier next time! I mean, like, strip the unnecessary functionality, put game design first (i.e. make an interesting game first), technical design second :)