how can I make traps for fruit flies
Small bowl with apple cider vinegar. Cover with plastic wrap and put a small hole in the top . The flies will get caught under the plastic once they enter.
Lots of tips for flies here: https://www.craftylittlegnome.com/flies-house-suddenly/
I use a banana slice rather than cider vinegar - works great, too
1 tbsp apple cider vinegar
1 tbsp water
a squirt of dish detergent
Take a 20 oz soda bottle, cut it 1/3 way down and unscrew top. Pour mixture in the bottom. Invert the top and place in the bottle. They will fly in and get trapped.