1-Turn Off Your Phone
2-Connect your Phone While Turned Off
3-Download and Install Lenovo SP Drivers
3-Extract the Scatter file and the recovery image from the rar files and put them in the same folder
4-Open SP Flash tool and choose the scatter file which specific to your phone model
5-Unplug your phone and press on Download in the SP Flash tool and replug your phone again
6-Wait till you see a green message telling you that the procedure was a sucess
All needed tools you can find it here in that link
http://www.needrom.com/download/lenovo-p70-a-p70-t-twrp-update/