Since the file is "decrtd" (decrypted), you can simply go to File > Load File and select the extracted .3ds file. :
If the file inside is a .cia , you will need to copy it to your SD card and use a tool like FBI to install it on a console with Custom Firmware (CFW). Security and Safety b10o-usa-decrtd-ziperto-rar
The filename b10o-usa-decrtd-ziperto-rar likely refers to a for the game Bravery Default (or Bravely Default: For the Sequel ), specifically the USA region version hosted on the Ziperto website. These files are typically used with the Citra emulator or on modded 3DS hardware. Since the file is "decrtd" (decrypted), you can
: Often a shorthand code for the game title ( Bravely Default ). usa : Indicates the North American region. These files are typically used with the Citra