First, get your access and secret key from here
Then embed it in the colab notebook.
%%writefile ~/.passwd-s3fs
AWS_ACCESS_KEY_ID:AWS_SECRET_ACCESS_KEY
Need to restrict access
!chmod 600 ~/.passwd-s3fs
Then install S3 file system.
!apt install s3fs
Choose local path(/s3), and mount the bucket name (here it's thainlp)
!mkdir /s3
!s3fs thainlp /s3
Now you can access S3 bucket as a directory
!ls /s3