Why my samsung galaxy j5 can't open after upgrading the android to android Marshmallow

[AC Question]

Hi I upgrading my android to Marshamallow yesterday and found that my Samsung Galaxy J5 always show the Samsung instead of opening the screen as usual. After I upgraded the android, it show that my phone will restarting continously and then my phone cannot be used anymore... why??? How can I solved this problem. Because the screen always blinking with sentence 'Samsung'. Please and thank you.