How do I let you know I don't need the arrival transfer to my hotel/ or the departure transfer from my hotel to the airport?

You can remove your arrival transfer to the hotel or departure transfer from the hotel up to one day before travel. From 14 days before your transfer, simply go to the TUI app, click 'Hotel Transfer', scroll down to 'Making your own way', and select 'Cancel Transfer'.

Just so you know, if you opt for alternative transfers, you won't receive a refund.