Between my day shift and night shifts, I hasve 3 off days.

No reason to have shift twice. You are talking about yourself, so you use "I have". You always have the pronoun in English

LFor the last few months, I will alsohave been working for a part time job during thatose 3 off days.

Need "for the". "Have been working" means you have been doing it since a certain point and are still doing it. Will be doing is the future. You are referring to multiple days, so use those instead of that.

Because no places yYou can't go. anywhere.

Don't end a sentence with a verb. Also, it is better to use "not go anywhere" instead of no places, because of stylistic reasons.

But now, most places are open again.

Comma after "but now"

For example, I can go to the library to read books, or go to the sport hall to play badminton with my friends.

Add "to" in between places and what you are doing there. Get rid of comma and add "or" because you are only talking about two things. Also, if you are referring to a place, use "the" for a specific library or sport hall, or "a" for any.

Also, I can have dinner with another 3 friends in restaurants.

No reason to have "another"

So, for the next few days, I will not working for that part time job.

add "for the" for passing time. Comma after next few days because it is a lead in into the main clause.

JI will just hang out and have fun with my friends.

No verb or personal pronoun.

Eat hard, Pplay Hhard and N, but do not work hard.

Use "but" instead of and because they are disagreeing.