About the book I have been translating for days--A Japanese dancer's dance trip

It's an interesting essay with many pictures. It is a story about a Japanese dancer, called Usa, travelling around the world in search of different dance styles. During the trip, he went to Ibiza, Spain for his first stop, which is well known as a PARTY ISLAND. Then he visited the savanna of Tanzania, where scientists have found the fossils of early modem humans who lived around millions of years ago. It is also said that the ancestors of humans all came from the African Continent. Usa, the dancer, visited a tribe there, where people dance in a primitive way with no music, but the beat of their heart. Usa joined the dance party, which was more likely a welcoming ceremony for Usa, the guest. And he found that even though they couldn't speak the language of one another, they could still communicate with each other through dance and the beat of their heart. And It turns out that we really do have the are all the same origins.
As for the third stop of his trip, Kenya, I am translating it now, and will share some interesting stories with you later~Stay tuned!

About the book I have been translating for days- A Japanese dancer's dance trip

It's an interesting essay with many pictures. It is a story about a Japanese dancer, called Usa, travelling around the world to search for different dance styles. In On the trip, he went to Ibiza, Spain as his first stop, which is well known as a PARTY ISLAND. Then he visited the savanna of Tanzania, where scientists have found the fossil of early modemrn humans dated from around millions of years ago. It is also said that the ancestors of the human race all came from the African Continent. Usa, the dancer, visited a tribe there, where people dance in a primitive way with no music but the beat of their heart. Usa joined the dance party, which was more likely a welcome ceremony for Usa, the guest. And he found that even though they couldn't speak the each other's language of each other, they could still communicate with each other with dance and the beat of their hearts. And so it turns out that we are all the same.
As to for the third stop of his trip, Kenya, I am translating it now, and will share some interesting stories with you later~Stay tuned!

About the book I have been translating for days- A Japanese dancer's dance trip

It's an interesting essay with many pictures. It is a story about a Japanese dancer,called Usa, who is travelling around the world to search for in search of different dance styles. In the trip, he went to Ibiza, Spain as his first stop, which is well known as a PARTY ISLAND. Then he visited the savanna of Tanzania, where scientists have found the fossil of early modem modern humans around millions of years ago. It is also said that the ancestors of humans (or: human ancestors) all came from the African continent. Usa, the dancer, visited a tribe there, where people dance in a primitive way with no music but only to the beat of their heart. Usa joined the dance party, which was more likely a welcome ceremony for Usa, the guest. And To his surprise, he found that even though they couldn't speak the language of each other, they could still communicate with each other with nothing more than dance and the beat of heart. And It turns out that indeed we are all the same share the same origin.
As to the third stop of his trip, Kenya, I am translating it now, and I will share some interesting stories with you later~Stay tuned!

Well done and good luck with your translation!

About the book I have been translating for days- A Japanese dancer's dance trip

It's an interesting essay with many pictures. It is a story about a Japanese dancer, called Usa, travelling around the world to search for different dance styles. In the trip, he went to Ibiza, Spain as his first stop, which is well known as a PARTY ISLAND. Then he visited the savanna of Tanzania, where scientists have found the fossil of early modem human around millions of years ago. It is also said that the ancestors of human all came from the African Continent. Usa, the dancer, visited a tribe there, where people dance in a primitive way with no music but the beat of their heart. Usa joined the dance party, which was more likely a welcome ceremony for Usa, the guest. And he found that even though they couldn't speak the language of each other, they could still communicate with each other with dance and the beat of heart. And it turns out that we are all the same.
As to the third stop of his trip, Kenya, I am translating it now, and will share some interesting stories with you later~Stay tuned!

Great. Just a few things.

I'd probably say "On the trip" or "During the trip" rather than "In".

..early modern human from millions ...

"from around a million" or "from millions" or "from around 1.3 million".

It seems for "around", you must state a figure.

Starting a sentence with "And" can be done, but also worth considering connecting it to the previous sentence and not using the full stop.

...they couldn't speak each other's language, ....

... and the beat of their hearts.

And It turns out that we are all the same.

very few corrections needed

About the book I have been translating for days- A Japanese dancer's dance trip

It's an interesting essay with many pictures. It is a story about a Japanese dancer, called Usa, travelling around the world to search for different dance styles. In the trip, for his first stop(1) he went to Ibiza Spain as his first stop, which is well known as a PARTY ISLAND. Then he visited the savanna of Tanzania, where scientists have found the fossils of early modem humans around from millions of years ago. It is also said that the ancestors of humans all came from the African Continent. There Usa the dancer visited a tribe there, where whose people dance in a primitive way with no music but except the beat of their heart. Usa joined the dance party, (which was more likely a welcome ceremony for Usa) as the guest, and. And he found that even though they couldn't speak each other's the language of each other, they could still communicate with each other with dance and the beat of heart. And it turns out that we are all the same.
As to the third stop of his trip, Kenya, I am translating it now, and will share some interesting stories with you later~Stay tuned!

change of word order to bring subjects and objects and related clauses closer together - like 'a tribe whose' rather than 'a tribe there, whose'