Every time I come upon these words, I get confused, because the meanings of them are either very similar with each other or have more than one meaning. For example, on goo辞書, the first meaning of 本書, shows to me 主, and this kanji has various meanings! Besides, it shows 文書, too (主となる文書). Apparently, 主 means しゅ, but I didn't understand very well the meaning of this expression 主となる (it becomes the main thing?). As you can see, when you try to understand 本書, you have to know if it's exactly the 主（しゅ）reading, the meaning of that expression and possibly of 主 by itself, and 文書. Very confusing for someone who doesn't have a deep Japanese knowledge. Besides, 本書 has more 3 possible meanings!
If I use an English-Japanese dictionary, like Jisho.org, I get only similar meanings without further explanation (everything looks like to mean "writing"; argh). On the other hand, if I choose a Japanese dictionary, like goo辞書, either I get more confused because hard new words are exposed to me, or one of these words from the title appears again.
Please, could you provide in detail the main meanings of these words? For example, in English, the word "writing" can mean more than 10 things! So, if you're going to use a word that repeats between the translations a lot, or that it has a translation of other word that can mean more than one thing, prefer to say, for example, "writing, as in...", or its contextually specific use (for example, apparently, 表記 seems to mean "to write on a surface", but is it the action, the result of it, or both? Is it writing on a surface like a table, or a paper on a table? Also, 文書 seems to mean something related with "paper", which I didn't find on goo辞書; I guess so). Furthermore, it would be appreciated if you explain the various meanings of a specific word, but that are in fact used. As I said before, for example, 本書 has 4 meanings, but are these 4 meanings really used?
I know that I'm asking too much, so if you say just the single and main meaning of these words, it helps me and the community a lot; I didn't find a post showing the difference between all of these words. I tried to do by myself, but I feel like walking in circles with the meanings (English is not my first language, maybe the word "writing" is straightforward to you, but I'm confused).