How can we get rid of gnats in our apartment?

Make a trap: [link removed]

It sounds like fruit flies to me also. The best way I found to get rid of them is to get a small clear glass jar with a wide mouth and not too tall. Take a piece of paper (printer paper will do) and roll it into a cone shape so that the sides of the cone touch all around the mouth of the jar and the bottom of the cone is about ¼ inch off of the bottom of the jar. Tape will help to keep its shape. Remove the cone for a minute then put about 1/8 inch of vinegar into the jar, replace the cone and set it where the fruit flies are buzzing. The fruit flies will be drawn to the vinegar and climb down the inside of the cone and wont be able to get out because they will try to get out by walking on the inside of the jar. The reason you have them is they naturally hatch from fresh fruit like bananas and pineapples. When there are half a dozen in the jar take it outside and remove the cone so they can fly away. Add more vinegar as necessary, replace the cone and use it again. It takes a few days to get rid of all of the flies but it does work very effectively