Lok Sewa 2083/84 calendar: Nayab Subba ad in Mangsir, Kharidar in Poush?

Planning my preparation from now. As per the 2083/84 annual vacancy calendar (effective from Shrawan 1, 2083), the ad months are:

- Gazetted first class: ad in Bhadra, written exam Kartik/Mangsir - Gazetted second class: ad in Ashoj, written exam Mangsir/Poush - Non-gazetted first class (Nayab Subba): ad in Mangsir, written exam Magh/Falgun - Non-gazetted second class (Kharidar): ad in Poush, written exam Falgun/Chaitra

So Nayab Subba vacancy should come next month. Exact dates only come in the official notice on psc.gov.np. Anyone who sat last year: how many months of preparation is enough for Nayab Subba first paper?

Source: https://www.kumarijob.com/blog/news/lok-sewa-vacancy-calendar-2083-84