In late August, 1985, I heldcarrying with me a dispatch certificate released by the Human Resource ds Department of Anhui pProvince, andI took a long distance bus from the city where I live now to Bengbu, and then took a train to the Jiashan County seat, where my first work unit was at / was located.

I’ve adjusted my correction based on your explanation.

The Jiashan County seat was on a small hill, so the roads there were not evensloped.

"Seat" in "Jiashan Count seat" is descriptive (not part of a proper name), so "the" is needed.

I’ve adjusted my correction based on your explanation.

I went to the(first) to the (county) agricultural machinery bureau (of the county first) to report for duty, and they told me that I was assigned to the bureau's subordinate unit: the agricultural machinery training class.

An officer at the bureau wrote me an introduction letter and lesent me go to the training class.

"Let me go" implies that you wanted to go, and the officer (finally) gave you permission to go. This isn't the same as 让我去 in Chinese.

"Sent me to" means the officer told you to go there. I assume that this is what you mean.

I left the bureau goingto go to my first work unit.

He said, j"Just go with me."

The work unit, which was also on the hill, which was very simple,(,) and only had a few rooms.

Your original wording meant that the hill was very simple and had only a few rooms.

The rooms awere connected in a row, from east to west.

There were no inclosing walls for the officenclosing walls for the office grounds. / The office grounds were not enclosed in surrounding walls. / The office grounds lacked the enclosing walls that would have typically surrounded a government office like this one.

Your original wording sounds like the building had no exterior walls---it was just a roof with some supporting poles, and wind and rain could blow into it.

I’ve adjusted my correction based on your explanation.

We (had) all majored in agricultural machinery management.

Since you were no longer studying (had already graduated), it's better to say you "had majored."

I started my career for the rest of my life this way, and I worked there till 1989 before I was transferred to my [home town].

By "home town" do you mean the village/town where you grew up? If so, you could add "back": ...was transferred back to my home town.

I left the bureau goingto go to my first work unit.

He said, "just go with me."

The work unit was also (on the hill/in the same building), which was very simple, and only had a few rooms.

Or maybe, "The work unit was in a building on the same hill, which was simple..."

The rooms awere connected in a row, from east to west.

There were no ienclosing walls for the office.