If you're a rank beginner, here's a basic list of 11 herbs to help your garden: http://www.motherearthliving.com/in-the-garden/companion-planting-herbs-to-help-your-garden-grow.aspx#axzz2wyeOtpvv
Here's a list of herbs and the insects they repel. Read the whole article - but the insect/herb chart is at the bottom: http://www.homeherbgardenanswers.com/cottage-garden-plants/
I really liked this list of herbs and companions by Darlene Widirstky from http://www.n8ture.com/herbalcompanion.html
Here's a mixed list of herbs and vegetables put out by Wasatch Community Gardens: http://wasatchgardens.org/files/resource/attachment/Beginning%20Organic%20Gardening%20Resources_1.pdf
And another mixed list of herbs and vegetables put out by Earl May: https://www.earlmay.com/media/cms/companionplantschart_25D154AE91635.jpg

If you spend some time with this, you'll see that everyone has a slightly different take on it and you may even find some flat out contradictory information. Don't worry about it. Just take your best shot and enjoy growing your own food.