Breakdown of kaisetsu o yomimashita.

Questions & Answers about kaisetsu o yomimashita.
It is read:
かいせつ を よみました。
Romanization: kaisetsu o yomimashita.
A small pronunciation note: the particle を is written を but is pronounced お in modern Japanese.
解説 means something like explanation, commentary, or guide/explanatory notes.
The exact translation depends on context:
- in a book or article: explanation
- for a game, movie, or event: commentary
- for something technical: explanatory notes
So 解説を読みました could mean I read the explanation or I read the commentary, depending on the situation.
を marks the direct object of the verb—the thing that is being read.
So in this sentence:
- 解説 = the explanation/commentary
- を = marks it as the thing being read
- 読みました = read
So the structure is:
[thing read] + を + [read]
In other words, を is the particle that tells you what the action is being done to.