My legs were sore,. I thought I caouldn't keep running today.

Those are two independent clauses, so you need a conjunction if you want to separate them with a comma (e.g., "My legs were sore, so I thought . . ."). Personally, I would phrase it as "My legs were so sore that I thought I . . ."

Couldn't needs to be past because in "My legs were sore" you establish it as a past setting.

So I decided to ride a bike to aAuntie's home.

Capitalize family titles ("mom/dad/etc.") when they're used as the subject of the sentence. In other words, when they replace the name.

So if your aunt's name is "Sue," the normal phrase would be "to Sue's home." Here, it's "to Auntie's home," so it's clear that "Sue" is being replaced by "Auntie" and should be capitalized. It also shouldn't have an article or possessive pronoun in front of it (the/a/my/her).

E.g. "It was my mom." BUT "It was Mom."

It was so hot in the afternoon, so I started at dusk.

It's grammatically okay, but having "so" twice in here is a bit repetitive. Could be "It was so hot in the afternoon that I started at dusk" or just "It was hot in the afternoon, so . . ." You could alternatively replace "so hot" with a different intensifier (e.g., "very hot," "too hot") or use a stronger adjective (e.g., "scorching," "blistering" [might have to add some word to make "blistering" work; check dictionary for usage]).

When I arrived, I was told that aAuntie had wentgone to the rice field.

I pulled up my trousers and walked cautiously.

Adverb, not adjective here.

Water was flowing in the small stream, i. It was so clear that I canould see the mud in the bottom.

Same problems as first sentence.

BA breeze was flowing.

This sentences strikes me as a bit off. I'd do something more like "There was a gentle breeze in the air" (preferably, "in the air" would be replaced with something more specific, like "caressing my cheeks" or something).

When I was on my half way there, aAuntie recognized me.

She told me not to approach because there were many ants.

I more commonly see "approach" used as a transitive verb, so I'd do "approach her," but should be okay in either case, so up to you.

And she asked me to go back to ask another auntie to help her.

I assume that's what you meant. This is a change of meaning, so just make sure that's right. What I put means that your aunt wants you to go fetch another aunt, whereas what you had originally means that she's asking you for permission for her to go back.

I picked some and tried them.

If that's what you mean.

Then uUncle picked some lobngans from another tree, which he thought would be more delicious.

"which" when used as a relative pronoun has a comma before it. Look up the difference if you want to know more (the other option would be "that").

That said, this doesn't work great because as is, the sentence means that the uncle thought that the tree would be more delicious, whereas I think you're trying to say that the longan from the other tree are tastier. I might just separate it into a separate sentence like "Then Uncle picked some longans from another tree; he thought they would be more delicious."

But I thought it tasted so normal.

Doesn't really fit.

So I stood under the first tree, and kept picking and eating.

I was so satisfied with thein that moment.

It's hard to be satisfied "with" a moment because that's kind of an arbitrary idea, whereas "in" just means that at that time, you were filled with a sense of satisfaction.

But I havedn't used the torch for a long time, and I didn't know that it was powered off.

Past tense for "haven't." "Used" is the past participle.

Luckily, I canould use my phone's light.

Whilen I was riding on the country road, I played music from my phone loudly.

There was moonlight, i. It was a little dim, but it was beautiful.

The comma is "proper" because when a coordinating conjunction connects two independent clauses, there should be a comma. But in pretty much every use (except maybe a test), it's not necessary here, especially because the sentence is so short.

E.g., "It was a little dim, but it was beautiful" BUT "It was a little dim but beautiful" (in the second, I removed the "it," so the second clause is no longer independent)

I saw a few fireflies, t. They shone and shone.

I went ton a night ride on the same road last summer, and I encountered many fireflies flying in the brushwoods all the way.

It felt like I was riding in the sky, which wereas full of stars.

"starry sky" might be better (fancier could be "star-spangled/star-speckled sky")

It was the most wonderful night ride in my life for now.

Or "It has been the most wonderful night ride in my life so far"