The first time I ¶
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The first time I went to our county seat was when I was in elementary school.

On ane early morning, we went to the county seat.

Your grammar is OK, but this is more normal.

Going to the County Seat

I haven't heard the term "county seat." I don't think it's wrong, but I would probably say something like "Going Into the City" or "Going to the City Center."

The first time I ¶
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The first time I went into our county seat was whenthe city, I was in elementary school.

How you said it is not incorrect, but this is how a native speaker would write it because you don't have to say "was when I was" you can just use a comma and it works.

One day, my father asked my brother-in-law to buy some coal. get some coal from the county seat as fuel for cooking.

The only vehicle we had was a man-powered wooden cart, which was used by everymost familyies for farm work.

On an early morning, we went to the county seatWe woke up early and headed to the city.

The county seatity was about 35 kilometers away from my village, which meant we wouldn't reachget there until the afternoon.

When we arrived at the county seatity, my brother contacted some people, and he quickly finished the trade process and loaded-in-law located the sellers and bought the coal.

Then, we immediately started returninged home.

The building in the county seatity that left a deep impression on me was a tall, red, and round water tower because it was totally different from the other buildings.

there is a rule in the English language called the serial comma rule or oxford comma rule. Basically, when there are three or more adjectives or topics listed in a sentence you add a comma between them and you add "or" or "and."

Everything in the county seatity looked new to me because I hadn't had any chance to go never been to an urban area.

you would say "I hadn't had a chance to go to to an urban area" instead of "any." I corrected your sentence based on how a native speaker would say it, but it wasn't incorrect except using "any" instead of "a."

When we arrived at themy town about ten kilometers from my village, it was already late at night.

We stayed at a small private inn, and ate a few cold steamed buns with water as our dinner.

We got up very early the next morning because we wanted to get home early.

We headed out early the next morning so we could get home early.

I felt very happy although I was exhausted.