I've tried using spray and powder pesticide to kill bedbugs before, personally I reckon powder is more effective. The brand I used its called Chinchex, kids and pets friendly, natural ingredients. They are not difficult to use, all you have to do is get a brush and a pair of hand gloves, let the powder sticks on brush and you just brush over the furniture.
Make sure you cover all the corners and gaps, even underneath the furniture. I remember they have a youtube tutorial video, you can have a look and check out their instructions on their website chinchex.sg
I hope it helps!