You should have an external SD card - Get the limonchelo ROM from the below thread and place inside the sd card using card reader from your computer.How to get out of the twrp loop? Can you assist by escalating to other gurus? Thanks a lot,
http://xdaforums.com/android/development/organized-thread-lenovo-k3-note-k50-t3158522
Then you may put the SD in the phone and go to TWRP. In TWRP choose Install the limonchelo zip from /external_sd folder.
If none of the method works, you have to do SP Flashtools method, and flash the ROW ROM
Procedure:
http://www.gizchina.com/2015/07/19/tutorial-stock-rom-cwm-google-play-lenovo-k3-note-k50-t5/