Okay kiddo, let me explain modern Hebrew grammar to you like you're five years old. Do you remember when you were first learning how to speak and your parents taught you about nouns and verbs? Hebrew grammar is kind of like that, but with some special rules.
In Hebrew, just like in English, we have nouns and verbs. Nouns are things or people, and verbs are what they do or what happens to them. But in Hebrew, we have genders - just like boys and girls - for our nouns. There are masculine nouns (for boys) and feminine nouns (for girls). Sometimes it's easy to tell which is which, like "girl" being feminine, but other times it's more difficult. For example, "book" is masculine in Hebrew, but "table" is feminine!
Another thing we have in Hebrew grammar is something called "conjugation." This means changing the endings of verbs depending on who is doing the action. For example, if I say "I climb," the word "climb" stays the same, but if I say "you climb," the verb changes to "climbst."
We also have something called "root letters" in Hebrew. These are special groups of letters that are used to make lots of different words. For example, the root letters for "to write" are K-T-V, and from those letters we can make words like "book" (which we already know is masculine!) and "author."
Finally, Hebrew is written from right to left instead of left to right, which can be pretty confusing at first! But don't worry - once you get used to it, it's not so bad.
So that's a quick overview of modern Hebrew grammar. It might seem complicated, but with practice you'll get the hang of it!