When were the mountains erected/created in the Qur'an?

Good day everyone! How to harmonize the time of the erection of the mountains in different verses? Before building the sky, this happened or after: 1) Before building the sky: Surah Fussilat (Explained), verses 9-12. 2) After building the sky: Sura An-Naziat (Throwers), verses 27-32.