Windows10 to Ubuntu

I have a Dell Inspiron 14-3452 that came with Windows10.  I forgot my password and the guy that was supposed to help me wiped out Windows10 and replaced it with an unregistered copy of Windows10 Pro. I deleted this and decided to go with Ubuntu. I downloaded the version for 3452 from the Ubuntu site and loaded it onto a Corsair FlashVoyager . When I try to boot from this I get: Could not find kernel image: Linux. Can someone please help me with this? I have been all over the internet and am getting confusing info about partitions and grubs and things that are way beyond my limited understanding of computers. If I can get some simple directions to follow I am sure I can make this work. I appreciate and am grateful for any help I can get, please. Thank you all !