They take (or assume) financial responsibility for themselves. They assume their own financial responsibility. (на себя = themselves, their own - Maybe the sentence wants to emphasize "themselves".)

English diary. Day 6

I tired today very much Today I am very tired. I went out from left my home at 8.25am and returned at 10pm. I worked, went to the gym and I had a Russian class. Tomorow Tomorrow I'm going to the game development conference. I hope it won't takes take a lot of time and after I will enjoy my weekend by watching TV shows and cooking healthy food.

Very good. You understand the phrase "...take a lot of time...". Well done.

Вы эффективны.

Вы программист? 

" I am a native speaker of Russian." <- это технически и грамматически правильно. "I am a Russian native speaker." <- это значит, что вы русские, и говорите на одном родном языке. However, in spoken conversation, people often use the first question you wrote.

Мне очень понравится разговаривать на английском и русском языках. Мне нужно практиковать грамматику и последовательность слов. Of course I can help you learn English! ;-)

Я программист. Мне очень нравится работать с компутэр с компьютерами. Мне нравится помогать людям, которые нуждаются в информации. А вы? What is your profession and why do you like it?

Мне очень понравится разговаривать на английском и русском языках. Мне нужно практиковать грамматику и последовательность слов. Of course I can help you learn English! ;-)

Another question about the slide

Hello everyone!

Could you please correct this these sentences if they are wrong?

If you want to come/ go/slide down this slide, you need to go upstairs up to the top, then pass/go to the slide, sit and slide down.
The stairs are over there. Be careful going upstairs/when you go upstairs up the steps!

Thank you for your attention!

Честно говоря, очень хорошо, Викторя.

Letter To a Sport Club

Dear Sir,
I have been attended your fitness club for about 2 years. Unfortanutely Unfortunately, I have to inform you I am going to leave the club.

I have a bronse bronze card membership, which gives me ability for attending of to attend the club 3 days per week within a half of year. I have been paying $600 for all courses.
I've really enjoyed being in your sport club, because you have the best sport facilities in the city,. your Your trainers are very qualified and they have always done their job as well as they could. After 2 years I feel very strong and I proud of my body, and it is all thanks to you.
The reason why I want to stop going to the club is that I have to move to another city due to my new job.
Thank you so much for your job work and supporting through all the time when I attended your club.

Yours faithfully,
Sergei I.

 

Very good sentence structure. Your sentences are complex and you use a lot of vocabulary. This was a pleasure to read!