They were our main food, and usually planted in May, and harvested in October.

OneFirst, they sliced the sweet potatoes into slices and dried them in the sun, and then collected them and stored them in houses.

TwoSecond, they dug cellars and stored sweet potatoes in the cellars.

People almost ate sweet potatoes for almost three meals every day.

"Almost ate" sounds like they did not eat but almost did. "Almost three meals" means most of their meals, which I assume is what you were going for.

It was so simple: you mixed the flour and a certain amount of water to make a dough, and then made the dough into many small doughs and flattened the small doughs, f. Finally, you stuck the flat doughs in a pot (water was at the bottom of the pot and didn't reach where the flat dough was sticking) to cook them.

Based on your description, "(water was at the bottom of the pot and didn't reach where the flat dough was sticking)", I think we call them "steamer pots". Your description is still clear and makes sense!

Colloquially in English, when describing a recipe or some sort of procedure, you can use "they" with past tense. For example:
"You mix the flour..." and "They mixed the flour..." sound more natural.

When people boiled this kind of sweet potatoes, they tasted more sweet than ordinary ones.

or "These kinds of sweet potatoes"

I grew up eating sweet potatoes andwith everyone grew up with itelse.

or "like everyone else."

Sweet potatoes used to be the essential food to feed us, but now people have more good alternatives to them, and they have become an exquisite dish in restaurants.

They were our main food andsource, usually planted in May, and harvested in October.

One, they way was to sliced the sweet potatoes into slices and driedy them in the sun, and then collected them and stored them in houses.

Two, theyhe second was to duig cellars and stored sweet potatoes in the cellars them there.

People almost ate sweet potatoes for almost all three meals every day.

Sometimes, people didn't even cut the sweet potatoes, but directly put themput them directly in the pot.

OneThe first was to crush the slices and put them into a pot filled with water to cook them.

People usually used the flour to make noodles and steamed buns.

It wa's so simple: you mixed the flour and a certain amount of water to make a dough, and then made the dough into many small doughs and flattened the small doughs, finally stuck the flat doughs in a pot (water wasseparated it into smaller units that you then flatten, finally putting them in a pot (with the water at the bottom of the pot and didn'not reach where the flat dough was stickinging the dough) to cook them.

When people boiled this kind of sweet potatoes, they tasted more sweeter than the ordinary ones.

I grew up eating sweet potatoes and everyone grew up with it, just like everyone else, eating sweet potatoes.

So tThere was a common saying in my area, "sSweet potato flour, sweet potato buns, without them we can't survive."

Sweet potatoes used to be the essential food to feed us, but now people have more goodbetter alternatives to them, and they have become an exquisite dishdelicacy in restaurants.