A nice way to celebrate the turn of the seasons with a simple yet effective craft activity is to go outside and collect things that are seasonal, bring them home and arrange them in some way.
The arrangement could be as a sensory box for instance. Simply get a shoe carton, put the items inside and a baby can explore the shapes and colours of autumn. An older child may want to try and guess items in the box by touch only, or arrange them into some sort of landscape (boxscape?).
Alternatively designate an area in the house as a season/nature area. This could be a plate, the mantlepiece, a bowl, or anything like that. Collect autumnal items from outside and arrange them to bring the season into the house. Let the children do this so that it’s their special display.