My fFirst noteEssay / Journal / Work / Piece of Work / Piece of Writing

Important words in a title need a capital letter. Note is more something you write as a reminder or use to casual information.

So, tThis is my first noteessay / journal / work /piece of work / piece of writing on this website.

Do not need the so.

Hi, my dear friendю.

Put comma after hi to separate it from my dear friend.

And I'm from Russia.

Don't need the and.

I'm start toed studying the English language 2 weeks ago.

"started" - past tense as something you did in the past. "studying" present participle sounds better after "started". It suggests ongoing activity. Although you could use "to study". "the" need the definite article as talking about a specific language. Connect with next sentence.

Aand I fiound this website on yYoutTube.

Connected with previous sentence so lower case "a" in "and". Past tense so "found".

MThe man from the video recommended this site, because this will help me learn the language to fast (sorry for my eEnglish).

"The man" and "the video" as you are talking about specific videos. "recommended". "will help" future action / prediction. "the" language as you are talking about a specific language. "fast" not "to fast". "English" has a capital letter.

So I start teach eed learning English with the textbook (in the beginning I wanted to write book, but iI think it is inot correct, so I wriote textbook) English Language Hub.

"started" past tense, "learning" or "to learn". You are "learning". The book is "teaching". "wanted" past tense, "to write" you need the "to form of the infinitive after "want" e.g I want to eat, I wanted to speak. "not correct" = "incorrect". "wrote" = Past tense. You can write book or textbook, both are correct.

I don't know if this textbook is good or not.

"now" an adverb meaning "at this moment". Need "if" or "whether" to introduce the choice between "good or not".

I'm tleachrning the present simple, the modal verb - have to, have/has, the prepositions (in, on, at), plural noun and demonstratives (this, that, these, those).

"I'm learning" - present continuous. Need definite articles as learning specific topics. Several "prepositions".
"this, that, these, those" aren't nouns the are "demonstratives" and they are not all plural.

That is all wthat I teach'm learning at thise moment (I hope, I used the correct to use preposition - at).

"all that" not "all what". I'm learning - present continuous as it is something you are in the process of doing at the moment. It is more usually "at the moment". Yes "at" is correct.