Net carbs is simply total carbs minus fiber and non-digestible sugar alcohols, like erythritol. (This doesn’t apply to high glycemic sugar alcohols, like maltitol.) We don’t have to count fiber and certain sugar alcohols in net carbs, because they either don’t get broken down by our bodies, are not absorbed, or are absorbed but not metabolized. (Read more about sugar alcohols here.)
Your body uses carbohydrates as its main fuel source. Complex carbohydrates (starches) are broken down into simple sugars during digestion. They're then absorbed into your bloodstream, where they're known as blood sugar (glucose). In general, natural complex carbohydrates are digested more slowly and they have less effect on blood sugar. Natural complex carbohydrates provide bulk and serve other body functions beyond fuel.
There are many Keto friendly foods that you can find at your local grocery store when shopping for a Keto Diet Recipes. Below, I’ve included links to a general shopping list as well as store-specific lists for your convenience. Make sure to print out The Very Basic Keto Shopping List to keep handy when you go shopping. Remember, you won’t need every item on this list, you can stock your Keto pantry as items are needed.
I personally don’t count anymore as I want this to be as easy and sustainable as possible. I have had years of counting calories and points, and this is incredibly liberating. I just don’t eat any sugars, grains or high carb foods any more so I am incredibly low carb all the time. When I was starting out I counted, just to see where my carbs were coming from and it was an eye opener. And yes you are correct, to go into ketosis anywhere between 20-50g carbs/day. Find out what works for you.
Use fat as a lever.  We’ve been taught to fear fat, but don’t! Both keto and low carb are high fat diets. Fat is our source of energy as well as satiety. The key to understand, though, is that fat is a lever on a low carb or keto diet. Carbs and protein stay constant, and fat is the one you increase or decrease (push the lever up or down) to gain or lose weight, respectively. So if your goal is weight loss, eat enough fat to be satisfied, but there’s no need to “get your fats in” once you’re satisfied.