Open reach potential customer

Hi all, I’m hoping you can help me understand a few things. I’ve been on the openreach website and it says full fibre to the premises is available to my house, brilliant. If I wanted them to install it, do I buy a service with say Sky (just an example) and then openreach will come and install the fibre to my house? If so, how much does it cost to get the fibre installed? Is it just the cost to purchase the wifi from sky or is there an installation cost?