Screen lock RESET on a brand New SAMSUNG M35

Upon powering on a New M35 I transferred files using SAMSUNG's on device utility from my old LG Q6 handset WITHOUT inserting any SIM Card ( as it requires first time SIM authentication of the specific Country Networks for subsequent usage) ; after 14days since then my charger arrived and I charged it 100%. Now when I power'ed ON the M35 it goes into SCREEN LOCK mode and I am NOT even able to OFF the device. I have NOT set any Passwords during my earlier activity, neither have I set-up the device properly for regular usage (intention being just to transfer data from the LG phone to the M35) . What could be the probable reason for the LOCK Up of the device and How do I disable the screen lock for regular usage of the device ?