Lesson 4: の means の: possession and attributes; bonus: honorifics
の is a particle. It's a possessive marker and an attributive marker. "Attributive" here means that something is an attribute of something else, like an attribute in a video game, like the "flame" in "flame sword". The relationship is always straightforward.
私のネコ My cat
君の Yours.
ネコの先 Ahead of the cat
男の子 Boy (metaphorically, male child)
If you get lost, the easiest way to remember の is: It's like "of", but applies backwards.
夜の人 Person of the night
Sometimes "of" gets confusing, and you have to remember the idea "attribute".
夜の海 The night sea
海の夜 Night on the sea (NOT "night of the sea")
の is literally the single most common word in all of japanese, so make sure you remember it well!
私の子供のネコが多い
My child's cats are many. (My kid has a lot of cats.)
Let's take a moment to learn about honorifics. If you're consumed any translated japanese media, there's a good chance you already understand this.
When referring to another person by name, their name usually takes a suffix like さん, くん, さま, or ちゃん. This is not an exhaustive list of honorifics, and they have a lot of context-specific nuances that would take a long time to memorize. Just keep in mind their function.
Just like the honorific titles Mister, Miss, Master, Sir, and Lord in english, japanese honorifics indicate the attitude the speaker is taking towards that person, and/or towards their relationship with that person. It's much less normal to use the honorific alone in japanese than english, so they act more like suffixes than independent extra words.
Referring to someone by name without any honorific at all might be familiar or intimate, or assuming of your interpersonal relationship with them. This is extra true if you use their given name instead of their family name.