sSaturday

Titles should always be capitalised

iI haven't writting dialy from then daily since last daytime...

"I" should always be capitalised no matter what, and the first letter of every sentence is always capitalised

"Since last time" is more natural here

bBut iI am going to write regularly from now on even one row.

"I" should always be capitalised even if it is in the middle of the sentence
The first letter of a sentence should always be capitalised

I didn't understand the last bit of the sentence, so I removed it. The sentence makes sense without it anyway

iI will aim for three days for now.

Future tense is needed for something you intend to do from now on, or in the future --> so I will aim for 3 days

iI went to the weekend Japanese school today.

iI borrowed a book about Egypt infrom a library at the school.

You borrow things FROM a library, a person, a store, etc

iI thought it was a good time to learn about Egypt.,

because iI went to Egypt this month.

I have added this to the previous sentence to make a single sentence, which will flow better.

mMy dad bought me 3 comic books 「case closed」, three books of this series for me, from the "Case Close" series.

We never use「」in English, we only use " ".

iI am looking forward to reading ithem in a bed tonight .

A bed = any bed
In bed = in your bed specifically

It = used for singular object, ie. just 1 book
Them = used for multiple objects, so includes all 3 of the comics you were just talking about

aActually,i I putted things off the things I needed to do, like, studying mathematic , offs.

"Putted" is not a word. "Put" is an irregular verb, in that is is mostly the same across all the tenses --> I will put (future), I am putting (present), I have put (past)

"Put off" is a phrasal verb, so it's probably better to keep the 2 words together to make it clear what you mean.

bBut taking care of myself is important to get motivation towards studying tomorrow.

sSo, iI am going to go to a bed earlier than usual tomorrow night.

To make it clear that you're not doing it tonight, but tomorrow night, it's good to specify that.

iI haven't been writting diaily from the last day...

The pronoun "I" is always capitalised.

"I haven't been writing daily" makes sense on its own but im not sure what you're trying to say after. you could try "I haven't been writing daily recently" or "I havent been writing daily the past few days"
Or if its only yesterday you didnt write you wouldn't say "the last day" as thats plural ,like "the last few days". you would simply say "I didn't write yesterday"

bBut iI am going to write from now on even one row.

I'm not sure what youre trying to say.

To say you're going to do it everyday would be "But I am going to write everyday from now on"

To say that you're going to write every day in a row is more complicated. Saying you're going to write "everyday in a row" sounds unnatural but still works, or you could say you're going to write consecutively. However, saying "everyday from now on" implies you'll do it everyday in a row anyway.

iI'm aiming for three days for now.

iI went to the weekend Japanese school today.

iI borrowed a book about Egypt in a library at the school.

iI thougt it was a good time to learn about Egypt.

Since the next sentence starts with "because", you wouldn't start a new sentence, you'd add a comma ( , ) instead as the "because" connects the clauses in the sentence.

bBecause iI went to Egypt this month.

mMy dad bought me some comic books 「case closed」, three books of this series for me.

iI am looking forward to reading it in amy bed tonight .

aActually,i I putted things to do ,like, studying mathematics , off.

mathematics is correct but sounds very formal, it's usually shortened to maths.

This sentence works but a different order, like "Actually, I put things off, like studying mathematics" might sound more natural.

bBut taking care of myself is important to gethave motivation towards studying tomorrow.

sSo, iI am going to go to a bed earlier than usual .