The stitch selector is located in the toolbar on the left and with it, you can create different stitches to design your knitting. Click on the stitch selector to open a menu where you can combine stitches as you like.
In this view, the colors you see on the canvas don’t represent the yarn colors, each color represents a different type of action. These are the basic actions and their symbol, they contain action for a single needle bed:
Transfer to front
Transfer to rear
The following symbols combine actions in both needle beds:
Knit rear and front
Tuck rear and front
Tuck rear and knit front
Knit rear and tuck front
Drop rear and front
When needles are lined up (default position of the needle beds, 0.0) it is not possible to knit in the front and in the rear bed with facing needles in the same path, they would collide. So all the rows where the racking position is 0.0 will be grayed out if Knit Front & Knit Rear are selected in the Stitch Selector.
The actions you want to combine may be possible once you rack the beds. Read more about racking here.