It is BEST to begin whatever MDS watercoloring project you want with the size and rotation of main image exactly as you want it in finished project, however recent updates to the MDS program allow you to do this later.
Starting with main image on blank page/card etc .... start applying Splatter image over each area you want to color - pick a color and change the opacity to suit your desired effect (I used 40% and 43% to create too shades). You will use MANY of these in various sizes and rotations - it is best to start with one size in the color you want and simply copy and paste it into all places want that size and color before moving to next size and color to do the same. Copy and paste becomes your friend in making this go more quickly.
Once your main image has been colored to your satisfaction (it will be hiding behind all the splatters) - bring the main image back to FRONT. Highlight the entire area and 'group' if you want to move the image around and still keep all the color where it belongs. The new update in April for MDS allows you to resize or rotate once grouped.
If you visit Mydigitalstudio.net and search Watercoloring ... you will find some other samples which are wonderful inspirations as well.