Obliviously, your best bet of surviving the initial phase of a nuclear war is to live far away from any city, military base, or infrastructure assets - these are all ground-zero.
If you are living near coast and are close to a city, a military base, or some vital infrastructure asset, you won’t get a warning of incoming nukes. A nuke launched from a sub off the coast can reach its’ target in under 5 minutes – that’s too little time for the nuke to be detected, identified as a nuke, a message to be sent up the “chain of command,” a decision made on how to respond, messages sent back down the chain of command and finally for the public to alerted.
Inland, you "may" get a few seconds warning of a nuclear attack. ICBMs take a bit longer to reach their target, so there’s a chance you could hear the national emergency broadcast system warning – a slim chance, but it’s a still a chance.
If you are 10 to 15 miles from ground-zero but have survived so far, try to get indoors and stay put as long as possible. Radiation decays exponential over time, so longer you can stay indoors the more the radiation has decreased. When you do finally go outside move away from ground-zero as quickly as possible and note which way the wind direction which is carrying nuclear fallout. Hopefully you are at home and have prepared by getting a gas mask, geiger counter, radiation suit and potassium iodine - now is the time use these. Remember, there could be multiple waves of nuclear attack that will target industrial and population centers so your goal is to avoid these areas too.
Great - you've made it through the intial blast. You have moved away from any potential targets, high-radiation zones and are out in the middle of nowhere (possibly your bugout location) - now what? You're are going to have use your judgement on whether you continue to stay here, or make your way to the southern hemisphere. Its likely that most of the war took place in the northern hemisphere so the jet stream will carry the smoke, soot and fallout around this half of the globe first. This is where any nuclear winter will start, so you'll have to decide if you'll be able to stay here long-term or if you should try to head "down under."