Hi, holistic development supports the whole child so alongside them finding out that they can use their hands on the wrap - by being part of the setup or by exploring it after? asking someone about the activity or watching someone else take part? maybe you can also have tools available for the children that want them? This would support a child's own thinking about the activity and the reasons why they're interested in having a go.
Using open ended questions will help tell you about their actions eg. if a child is keen to develop new skills, practicing exisitng ones, some children may also have sensory concerns about using paint on their bare skin/hands so tools would make sure the activity is inclusive.
What you've said about this activity encouraging the different areas of development reads nicely :) if it helps there's a
creative activity planner on this thread that you might use to focus or highlight what you're doing.
Maybe you could also think about ways the activity can be expanded so children's interest and concentration stays focussed eg. having dried autumn leaves that can be stuck to the surface of the paint, creating a design?
Very best wishes with it xx
Holistic development
& 
Linear Mode
