How to Increase Stitches

When a crochet pattern tells you to "work 2 dc in the same dc st", what does that mean, exactly? Here are a few examples:

To increase at the beginning of the row, work the first stitch in the base of the turning chain, as shown above.

To increase at the end of a row, work a second stitch into the same spot as you worked the last stitch in that row

To increase in the middle of a row, work another stitch into the same stitch as the previous one.