on the TV itself (not the remote). While holding the button, plug the power cord back in.
The file is a firmware update file for specific TCL Android Smart TVs , notably the P2US series (such as the Download S68AT02 LF1V198 part06 rar
For official downloads and instructions, it is safest to use the TCL Support Page or contact their regional service centers. TCL Electronics - Facebook on the TV itself (not the remote)