There life span is only a few days so soon they will be gone.
One simple to make trap is to take a plastic cup and drill a 1/4 hole in the bottom of it. drop in a slice of apple and tape another cup on top of it at the seam. then flip it over.
The flys can get in but can not figure out how to get out.
I do a variation of what joecaption said. I take a bowl and put about a cup of vinegar in it. Then I put some plastic wrap tightly over it and punch several small holes in it. The flies are attracted to the vinegar and they can get in but can't get out. Works like a charm for me.
Put vinegar, beer, wine, fruit, juice, or/and piece of fruit in bottle, put funnel in bottle. With a holed cork you can make one that hangs upside down, spout of funnel above level of liquid. Flies fly up to escape never find opening. You can buy decorative ones that don't look like bottles hanging all around, some sit on counter tops. They also catch house flys 'cause of bigger entry. Never tried beer as bait, seems like a waste of good beer, I ain't sharin with no fly. Wine is real good bait.