With the Box and Rindle integration, there is no major setup or configuration.  It's all built in. You can quickly and easily enjoy your Box files in moments.  All that is necessary, are the login credentials to your Box account. 

From within a task, select the blue Add Files bar, and Rindle will offer the four file attachment options.

Select Box.

You will be prompted to enter your Box credentials.   Once you have done so, you will see your Box files in the pop-up:

Check the box to the right of the files you would like to upload to Rindle.  Select Choose.  

Once the file has uploaded to Rindle, you will see it appear as any other file in the task, and also the Files View of the board.