Change the color of an object, by selecting your Object 
or Sub-object 
and tap on the Color 
button on the toolbar.
This will display the color gradient.
Tap or drag your finger over this pallet to find the perfect color for your object.
If you want the colour to be the same across all Steps hold down on the Colour button until the Replicate Flower pops up.
Here you can copy the colour attribute across all steps by pressing the Across All Steps 
button on the Flower.