In the example, the increase that corresponds to the decrease shown on the first stitch (stitch #12) is the yarn over to the right of the decrease stitch, stitch #11 (image 2).
The first row worked is a right side row, so the chart is read from right to left. We begin on stitch #12, and to continue working to the left we work stitch 1, then 2 and so on across the chart to the left.
Because stitch #11 (the corresponding increase stitch) is not worked at the beginning of the row, but stitch #12 (the decrease stitch) is worked, then stitch #12 should NOT be worked as a decrease stitch, but instead worked in Stockinette Stitch on the first stitch of the row.
This maintains the same number of stitches across the row without any unintentional decreasing.