secretariat annexe, unit

[user_gary]

Lucknow, Oct 18 (PTI) Uttar Pradesh Chief Minister Mayawati today assured mediapersons that her government would provide all possible help to them in discharging their professional obligations. She was visiting the newly-built media centre in Lal Bahadur Shastri secretariat annexe which also has her office.
The BSP chief, who had inaugurated the media centre on October nine, the death anniversary of party founder Kanshi Ram, said the unit, which has all modern facilities, would help the journalists function better. PTI.



Please explain the emboldened parts/words to me.

[Anglika]

Lucknow, Oct 18 (PTI) Uttar Pradesh Chief Minister Mayawati today assured mediapersons that her government would provide all possible help to them in discharging their professional obligations. She was visiting the newly-built media centre in Lal Bahadur Shastri secretariat annexe which also has her office.
The BSP chief, who had inaugurated the media centre on October nine, the death anniversary of party founder Kanshi Ram, said the unit, which has all modern facilities, would help the journalists function better. PTI.



Please explain the emboldened parts/words to me.

The secretariat [ the department dealing with administration ] has an additional office building.

The unit refers back to the "newly built media centre".