How do you help your child know what's happening each week?

My partner's child is autistic and I'd love to hear how other parents and carers handle this. Do you use a visual timetable, a board, your phone, or nothing in particular?

How do you prepare your child when plans change at short notice, or when something unusual is coming up, like a dentist visit or a new place?

And if grandparents, a co-parent or school are involved, how do they know what's planned?

What works, and what's been a struggle?