Step one is to find a saddle that you are comfortable on. You can do this by trying a bunch of different saddles at your local bike shop, to see what feels good for your specific body.
There is no one saddle that is good for absolutely everyone but split nose saddles like the ISM saddles tend to work well on tri bikes. Females tend to do better with female-specific saddles from a company like Cobb. After that, your back end takes a few years to adjust to that much riding and there’s really no way around it other than putting in lots of miles in the saddle.
Pro Tip: Get yourself some good DZ Nuts chamois cream to prevent you from getting saddle sores (which make riding really uncomfortable.)