A lock stitch is a "stay in the same place stitch". Or length set at zero, like when the feed dogs are down. It will lock the stitches and let you go on. You probably have a button to do this. My Janome has a button on the front and it makes 4-5 in place stitches and stops.
Burying the stitches means to take the tail ends and pull them in between the layers of your quilt. If you use the lock stitch, you should be able to clip the tails and not worry about them "unstitching" themselves.
Lock at the beginning of your sewing, and at the end, skip to the next area and repeat.