Dear Historians, looking for a agreed upon, evidence supported timeline of who has inhabited Palestine from as far back as possible. Were there any non-jews there before? Trying to get my head around the modern day conflict. Thanks in advance.
As far back as possible would bring you well into prehistory. Early humans spread from Africa across the world one to two million years ago. The Middle East (including what is now Israel/Palestine) would have been the first region outside Africa to be populated.
Modern humans (Homo Sapiens) are distinct from those early humans (Homo Erectus etc.). Modern humans also evolved in Africa and spread from there across the world, starting some 150.000 to 200.000 years ago. Again, the Middle East would have been the first region to be populated outside of Africa.
Effectively, what is now Israel/Palestine has been inhabited since forever, as far as human (pre-)history is concerned. There were no Jews back then; there were no Palestinians back then.
I realise this won't help you wrap your head around the modern day conflict, but I hope it helps you understand that any "we were here first" argument is dubious at best.