Welcome to this user forum.
It probably looks like this.
There is nothing you need to do. Once the order has been placed, BT Retail will arrange for Openreach to provide the connection from the exchange, to that socket.
Provided all of the external network has been completed by Openreach, then it should be possible for that to happen in a reasonable time.
The problem is with new builds, is that quite often the external network is not complete due to blocked cable ducts. This can take a long time to sort out.
It does not sound like you have a problem, so I would wait and see what happens on the 18th Jan.
They wouldn't know about a blocked duct until someone tried to shove a cable through it.
Most installs go OK with no problems. The only ones you get to hear about on this forum are the ones that went horribly wrong.