Sounds like you are a newbie - welcome to the group.
I don't know what you know, so stick with me:
Before you "baste" your quilt, you need to sandwich your quilt which means you put your top, batting, and backing together in the right orientation. It is VERY important to keep the backing taught, the batting flat, and the top nice and smooth. The better that part of the sandwich is constructed, the better your quilt will handle during quilting.
I use pins to baste my quilt (or hold all three layers together) and I place the pins approximately one hand-width apart. However, BEFORE I pin, I plan my quilting lines so I don't place pins in the way of the quilting line.
Once pinned (basted), I roll the quilt in half and sew down the seam lines. First in one direction and one half of the quilt then the other. My machine uses a Stitch-in-the-ditch foot that makes following the seam line easier.
Hope that helps. Have fun.