A day in my life

After I've learned, it's five to eight, so I went out of my home and went to company. > After I finished studying, it was already five ( minutes) to 8. ( You study to learn)
It's twenty past nine when I arrived. > It was twenty past nine when I arrived at my office.> By the time I arrived at my office, it was twenty past nine.

There is no one and I poured myself a glass of water, then I begun read book.> There was no one there yet, so I poured myself a glass of water and then proceeded to read a book.

Note > proceed to do something  = to do something after you have done something else.

I always arrived company earler than others.> I always arrive at work earlier than the rest.
As I'm now planning for losing weight，I only bought a bread at store in basement 1st at noon. > As I am planning on losing weight, I only  bought  a small piece of bread for lunch from a store located in the basement of our office building during my lunch break at noon.
It's very hot at company, so I'm very sleepy, then I take a nap on my desk( sleeping on top of your desk).> It was very hot in my office, and since I was feeling very sleepy, I decided to take a nap at my desk. ( Use the past tense. All these happened in the past)

It's about five, I realized I haven't write article yet, so I opened my notebook at once/immediately, and I wrote a article about my life today.> It was not until about five that I realized that I have not written anything on my notebook yet, so I quickly opened my notebook and then proceeded to write this essay, which is about how I spent my day today. (At once/immediately = instantly. Your notebook was not in a place where you could do that at such speed > So, I immediately took out my notebook and then proceeded to ...)

Now, I'll sent this article on italki, and there are many kindhearted friends will correct it.( You have already posted it here, so don't use "will" ) > Now that I have posted the very essay on Italki, I hope some kind- hearted friends will correct it for me .

The very essay = the essay that I am taking about/ exact/

Thank you very much!

A day in my life

Well written! Most of the correction was keeping it in the past tense when telling a story that took place in the past.