I'm assuming you're a fairly new reloader by your question. That's great, keep asking questions!
As a baseline start with the loading manuals Cartridge Over-All Length (COAL AKA COL) for that bullet, in your chosen bullet weight.
To tailor your load for your rifle, once you've found a propellant charge weight that groups best providing the velocity range you wish to achieve, you can find the ideal COL for your rifle with that bullet with some measuring and experimentation. As suggested earlier, there are numerous measurement methods to determine distance to the rifling. The Nosler manual suggests one method, other manuals provide sound techniques too. Softer, conventional bullets generally "like" a shorter jump to the rifling, harder, monolithic (all copper or guilding metal) might like a bit more of a jump. Not always.
Be watchful of COL and magazine length! Take your time and enjoy the process.