A song in the Immortal Sword and Sorcery 4 video with lyrics like I don't know what I'm doing as a teenager until the streaming shadows dance into sleep. Please answer

It's Dong Zhen's "Back to the Beginning"

Here's the link to the video and the lyrics

Just a young man, with a three-foot longsword, his heart is not tied to the cloudy sky

Guarding the thousands of mountains, not afraid of the danger of the journey, but it is difficult to get the heart of the people in turmoil

When will you ever dream of returning to your dreams in the quiet mountain peaks

One love to the end of all the laughs

We always can't understand that heavenly way is not a sword

Yes but also not.

I didn't know how to pick the stars until the fireflies fell asleep

Iris blossomed like the old face

The bow fell on the moon to pay for the parting, and the hearts of the old people were tired of the dashing

The next story will be back to the beginning

Through the years, I dreamt of going back to the waterside to watch the fireworks bloom under the moonlight

The parting was also difficult, but how could it not be shortened, and leave the lonely lamp behind

The sound of the piano broke my fingers and the string was broken. The sound of the zither breaks the strings

Who do I play for in my life's frustration

Some sorrows, some sorrows

It's ridiculous that my life is in the hands of God

I didn't know about picking stars until the fireflies danced me to sleep

Iris blooms are like the old days

It's the moon in the bow and the dashing of the old man's heart is already weary of him

The next story is back to the beginning

The next story is back to the beginning

It's a story that I have been waiting to read.