How minimum runway length is calculated for PAC P-750 XSTOL?
You can't, at least not on the basis of the POH you linked. Taking off with 0° flaps for that aircraft is outside the POH limitations chapter.
2.20 Flap Limitations:

Approved flap ranges.
TAKEOFF FLAP: 20°
LANDING FLAP: 40°

4.27 Amplified Procedures - Normal Takeoff):

A wing flap setting of 20°  is recommended for all takeoffs. 20° flap
will provide the best takeoff performance. The Normal Takeoff
technique is to be used for Short Field operations and is the
technique used to derive the performance data in Section 5.