More Detailed Explanation
In section 8 of the Piano Bundle: Downloads - under the first first heading of 'Chord Charts' the first chart identifies the 7 notes that make up the basic pattern in DecPlay. Each 7 notes from 1-7 form an 'Octave'.
When you run into the difficulty that you are experiencing to make the space where your hands overlap the most simple thing is to move one of your hands up or down an octave. In order to decide which hand you move, you simply try it and see which 'sounds' best.
Start off by keeping your left hand playing the chords as you have them and move your right hand up to the next Octave. Where you are currently starting on note 3 , you move up to the next note 3. If the melody then sounds too high for you, return your hand to it's original starting point at the lower note 3 and move your left hand down to the lower chord 6. I would suggest keeping the original chord 1 that you were playing and just use the chords 6,4 & 5 in the lower octave.