Its rare to find data for a particular brand of bullet you just happen to choose using a powder companies on line free data but there will usually be data for a bullet of the same weight and that is the data to use. In this case the data is for a Hornady 115gr XTP.
You need to use good hand loading procedure and develop your your load from the calculated or listed start level working up while watching for pressure signs and looking for best accuracy and velocity. The start load will produce shootable ammo but it may not be the most accurate or the highest velocity.
With N320 the start load is 4.0 grs and the max is 4.5 grs so in this case you can load 10 rounds at the start load and 8 at year level in 0.1 grain increments using a box of 50 cases to give you a load at each charge (4.0, 4.1, 4.2, 4.3, 4.4, 4.5). Test the lowest charge first and then the next heavier charge, look for pressure signs and stop if they appear making the previous load the maximum.