One of the easiest ways to engage kids (and yourself) in mindfulness is to colour a mandala.
Print and colour this mandala while practicing mindfulness – pay attention to each moment as it arises, the sound of the crayons, the movement of your hands, the various feelings that arise from using various colours. Notice the stillness of the mind as you focus your attention on what you are doing….Notice your breathing…..Notice the feelings in your body.
You can of course also draw one of these for yourself, like I did. Or draw one for your child that is simpler perhaps and easier to colour. Something like this maybe…
There are loads to choose from on the net, just google “mandalas for children to colour”