Regardless of your chosen service provider, Openreach (or contractors working for Openreach) will use the same method of entry as that currently used to deliver the existing metallic pathway. Hence, in your case, it will be via the existing duct(s).
Externally there may be a customer splice point (CSP) installed, at ground level, in place of the existing capping at the end of the duct.
Internally, an optical network terminal (ONT) will be installed. Your access will be via an Ethernet port, to which your router can be connected. (It is similar to the original method of supply of a VDSL2 (FTTC) service, when an Openreach modem was installed.)
[Subsequent edit to correct a typo.]