Read this article and watch this video to learn how to create half cardigan knitting.
To create a half cardigan structure in the software, first create a double jersey structure.
Now add a row of combined knitting and tucking on every other row. You can choose to knit in the front and tuck in the back or the other way around. With half cardigan you want all these rows to be the same, but in full cardigan you want to alternate between having the tucks in the front and rear.
Open the stitch selector in the toolbar on the left, and select either 'Front Knit' and 'Rear Tuck' (left) or 'Rear Knit' and 'Front Tuck' (right).
Below a detail of full cardigan knitting.