Most of the diaries you would consider to be yearly diaries, are actually treated as monthlies in Q++Studio (eg. 12 months on 2 pages, etc…). The use of a yearly grid structure in Q++Studio is rather rare.
The cases in which a Template's structure is set to yearly, usually involve a grid with only one DayValue per page and then 12 (or even 24 or 26) MiniCalendars to display a year or more in MiniCalendars. When you scan this kind of GridTemplate, because there is only one DayValue of 1 per page, Q++Studio proposes a day/page structure, which you then override.
Use the Start On option to determine the date which corresponds to DayValue = 1. It can either be the first of the year (January 1st) or the beginning of the week that contains January 1st (in that case, which weekday it is will be determined by the Week Starts On setting of the GridOptions).