Hi ,¶
I just want to see how it works.

Greetings like “hi” tend to have a comma afterwards.
You can remember this by thinking how you would say it. You wouldn’t hear someone saying “hi I just want to see how it works” really quickly and without any breaks unless they were trying to get a word in without being interrupted. Typically there’d be more of a pause after the “hi”, so that’s where you would put the comma.

MaybeI bought a book around 2 or 3 weeks ago I bought a book.

It sounds more natural like this, but there wasn’t anything grammatically with how you had it originally as far as I can see.

It's called ‘50 sSteps to iImproving your aAcademic wWriting’.

It’s better to have some way to distinguish the name of the book from your actual sentence. You could also use double quotation marks (“ ”) instead of single ones (or maybe that’s what you should definitely be using? I’m honestly not 100% sure).

However I 'm learning without a teacher and I use it as/like a self-study course.

Remember to include an article (“a”).

You could keep it as “like”, or alternatively you could also choose to use “as” instead.

So, I need help towith checking my texts.

Your original sentence worked as well, but there’s a slight nuance between the two.
I think your original sentence kind of has a bit more of an emphasis on you being the one who checks the texts. It also feels like a very general thing, like you’re saying that you need help but aren’t necessarily asking for help.
My suggestion feels a tiny bit more like you’re telling people that you need help and are actually asking for their help.

But it’s a VERY slight nuance so it doesn’t really matter too much.

I think it’s also kind of just how it sounds. Personally I prefer how “with checking” sounds.

Let see how it will be?.

I think the “let’s see” kind of makes it feel like less of a question, so having the question mark just implies that you’re not confident or that you’re uncertain about what you’re saying.
Of course that could be what you’re saying in which case you can definitely keep it like that. But just a note that I think this kind of usage with question marks is a bit more casual since I don’t really see it being used in more formal situations.

If you wanted it to be a question about how it will be though (like what will come out of this) then you could say “how will it be?” or something like that.