If you think you know which room your hamster is hiding in then close all the doors in that room so it is less likely to leave, although it is still possible it could chew through a door. You can then setup a safe trap to catch your hamster over night. If you are unsure where it may be then leave all doors open or set up separate traps.
Also leave your hamster’s cage open on the floor with some food inside near the place you think your hamster is, or in the room where the cage is normally placed if you are unsure. It may be that your hamster is happy to return to its home and you find it asleep in its cage when you wake up in the morning.
To set up a safe trap for catching your hamster, first find a container with high sides such as a bucket or basin. This container should be at least 12 inches deep to prevent your hamster from jumping or climbing out, and even deeper if possible. Syrian hamsters in particular will require a deeper container, as will Roborovskis, who can jump surprisingly high given their small size.
To enable your hamster to climb into the container you will need to build a ramp, for example by using a wooden plank or a wire shelf, or alternatively a staircase, for example by placing books or magazines on top of each other and giving them some support underneath.
Next place a few layers of tissue paper or a thick towel in the container to provide a soft landing if your hamster jumps in.
Finally, put some suitable treats with a strong smell in the container, such as cheese or slices of apple. Also put a few small seeds on the ramp or steps, but not so much that your hamster will eat these and then leave. Your hamster will hopefully follow this trail and then smell the food in the container before investigating further.
After finishing the trap, turn off the lights and leave it overnight before checking it in the morning. It may be necessary to leave it for several nights, so do not give up too soon and make sure you replace the food with fresh treats each evening.