Most people ask the question, Where do I start? I would honestly answer to anyone that asks this question this: What do you need most to survival? The simple answer is based on what you actually cant go without and for how long:

---------CHART-------------

3 minutes ----- without air
3 days----------without water
30 days --------without food   

Air: To filter air, you will need a gas mask, you can make a simple effective one by using activated charcoal, a thick mask from a hardware store, and a sock or sort of cotton fabric and glue. All you need to do is drill a hole in the mask , but on the inside you need to have the activated charcoal secured by a sock, and glue or stitch the sock onto the area around the hole(NOTE that this mask will help filter air but certain gases like hydrogen sulfide will neutralize the effectiveness of activated charcoal but will still be great for forest fire smoke and sandstorms.

Water:  Another great use for activated charcoal is for water filtration and it is re-usable for all those environmentally-friendly people out there. Although there is many other ways to filter water from creeks and streams, like AquaTabs and LifeStraws, If you cherish the old ways of our ancestors or just want a simple solution for filtering water, I would use activated charcoal.

NOTE: that a half-pound or 227 grams will filter 800 gallons or 3600 liters of water.

Food:  With food there are many options from growing a garden, foraging, hunting, or raising your own livestock...But for modern people that buy at the super market here is a tip...buy extra canned goods and set them away for emergency stock. for example, if you only need 1 or 2 cans of baked beans, double it. so instead of buy 1 buy 2. There are many easy foods that you can grow very easily. here is a  short list of easy tubers anyone can just put in the ground in the fall and the winter rain will water it for you without you even touching it once.

Potatoes
Onions
Carrots
Garlic
Turmeric
Ginger
Leeks

All you need to worry about is planting in good quality soil and nature will do the rest. After four months, you can harvest. Also in regards to foraging, there are many plants, mushrooms, wild greens ect. that you can harvest in certain seasons all over the world...Check your local laws and most countries you can either buy books, learn from one that is already experienced in this field, or take a class on such at your local community center.

WARNING: Do NOT Harvest wild mushrooms without prior knowledge and proper identification skills. Do Not Risk it. Always know what your looking for.

Thank you for reading, Happy Prepping and have an excellent safe day.