In old ancient times wheat was eaten straight. No milling. And this is certainly an option to you and should be considered when in a survival situation. But this is not a good long term option as it is very hard on your teeth. At some point you will need to learn to mill your wheat.
Milling can be as simple as crushing the wheat seed between two stones. This is certainly hard work. And ultimately you will want to find some sort of machinery to mill the seed for you. The three most popular power sources in the past were animal power, wind power and water power.
Hand Grinders
Hand grinders come in a variety of sizes and you need to get one now. You can use the old stone on stone method but try that before the SHTF and you will soon realize that a hand grinder is a wise investment. You can also buy electric grinders but when the power is down the hand grinder will be invaluable.
Once the wheat is ground into flour you can store it in a dark cool place just like the wheat. But flour degrades nutritionally extremely fast once it is milled. So it is better to grind the wheat as you need it.