I've observed that when converting CSV data to T6 format, the datetime parameter appears as a decimal value. The integer part before the dot represents the number of days since January 1, 1900. The fractional part after the dot represents the time of the day in decimal format. For example, 45000.5 corresponds to 45,000 days after January 1, 1900, at 12 noon.

And keep in mind for t1, stand for time plus one data point, which is either ask or bid price, you don't have three field to populate.
Ask and bid prices are represented by positive / negative values. Check the manual for details: https://zorro-project.com/manual/en/history.htm

typedef struct T1
{
DATE time; // UTC timestamp of the tick in DATE format
float fPrice; // price data, positive for ask and negative for bid
} T1;