Yesterday it was athe first day back at work after my short week break.

This correction makes it more clear that this is not your first day ever at this job.

I will work in a restaurant as a barista.

No “will”, because you already do.

Most of my colleagues wereact very pleasant to me, and asked how was my work was abroad, and whether I missed my country or not.

For me it's the 3rd time abroad, so it was easy to adapt into the new place.

By the way, I had very big chances because in my first day at work was a holiday.

Chance for what? I’m a bit confused about this sentence, so I just added a comma.

A lot of guests coame to our restaurant and the flow of guests was horrendous.

Guests is plural, I’m guessing, and “came” is in past tense to match your use of “was” later in the sentence.

So yeah, my day was little bit tiring, also we have made general cleaning, meeting.

I am not sure about the meaning of this sentence, but it’s not grammatically correct.

At the end we finished at 3am, and when I coame home I doid my aftercarnightly routine, and just fell into my bed.

“Nightly routine” is much more commonly used than “aftercare”. Also, remember to conjugate everything in a sentence to the past tense when you’re talking in the past tense!

Yesterday it was amy first day at work after mya short week-long break.

Your sounds as if the week was shorter than usual rather than you went on a short break for a week

I willam working in a restaurant as a barista.

I changed this to the present tense as you go on to describe your work so this is a job you are already doing not something you will do in the future

Most of my colleagues wereact very pleasant to me, they asked how was my work abroad andwhat work i had done abroad and whether I missed my country or not.

I assuming that your colleagues were asking what you used to do in you work overseas

For me it's 3my third time abroad so it was easy to adapt in the new place.

You wouldn't usual use the abbreviaton of an ordinal number in a sentence. They are usually used for lists.

By the way I had very bigmany chances to demonstrate my abilities because in my first day at work was a holiday.

Its not clear what you mean by having bis chances, I've assumed you mean your were anle to show your colleagues what you could do given your previous experience.

A lot ofMany guests coame to our restaurant and the flow of guests was horrendous.

So yeah, my day was little bit tiring, a. Also, we have maddone general cleaning, and had meetings.

At the end w We finished at 3am, when I comegot home I doid my aftercare, and just fell into my bed.

No need to mention at the end, this is implied.

First dDay at wWork

Title capitalization rules

Yesterday it was amy first day at work (after mya short week break after my last job?).

"My first day at work" is to say your very first day at this job ever, so as a reader I am wondering what you mean by "week break"

I will work in a restaurant as a barista.

Note, if the restaurant primarily serves coffee and tea but also offers some pre-made snacks and sandwiches, this is a cafe. In fact it would be pretty unusual for a restaurant to have a barista. Typically cafes have baristas serving drinks (think of Starbucks), while bars (or restaurants with bars inside) have bartenders serving alcoholic drinks.

Most of my colleagues wereact very pleasant to me, and asked how was my work was abroad and if I missed my country or not.

"React" is not typically used in contexts of normal introductions or conversations

For me it's 3It's my third time abroad so it was easy to adapt into the new place.

By the way, I hadwas very big chanceslucky because in my first day at work was a holiday.

A lot of guests coame to our restaurant, and the flow of guestcustomers was horrendous.

Used a synonym to avoid repeating "guest"

So yeah, my day was little bit tiring, a. Also, we have maded a general cleaning, meeting.

At the end weWe finally finished at 3 am, w. When I coame home, I do my aftercare, and just fell to my bedjust got ready for bed and fell right asleep.

"Get ready for bed" is kind of a set phrase that is all-encompassing for what we do before bed. This can include: changing into pajamas, brushing your teeth, washing your face, using the toilet etc., basically any of these little things you do as preparation.

"Fell into bed" was fine, I just changed it to avoid repeating "bed" with the previous edit