You check a chart for errors automatically, by checking whether there are too few or too many stitches in a particular row.
The number of stitches produced by the previous row, must be the number of stitches used by the next row.
This feature is only applicable to knitting charts.
In the menu, click "Check chart". When checking your chart, you'll get an overview which shows you for every row:
The number consumed and produced for each kind of stitch can be customized by clicking with your right mouse button on the color/symbol in the palette at the left side of your screen.
Repeats are indicated by enclosing the stitch into lines which you can draw. After drawing the lines, click with your right mouse button on the color in the palette at the left side of your screen to set the repeat count on the 'More' tab.
Start now designing your own first pattern!