My perspective on The Terminator timeline.
Since I'm not so good on picking upon the dates in these films I'll just go through explaining the events with the dates.
Point #1)The Birth of the Terminator Universe
"Sometime in the future John Connor will send Kyle Resse back in time to impregnate his mother so the survival of the human race is ensured"
Point #2)The Events of The Terminator(1984) take place
"Rather self explanatory"
Point #3)In between The Terminator & Terminator 2:Judgement Day
"In between time between films Sarah goes rouge trains her son & gets into plenty of bad relationships.While that is occurring the remaining debrea from the final fight scene in T1 gets discovered and leads to Skynets creation"
Point #4)The Events of Terminator 2:Judgement Day take place
The first four points in the timeline are set in stone as the general basis for the Terminator franchise the next two are choose your own adventure and neither is right or wrong.
Point #5a)The Events of Terminator:The Sarah Conor Chronicles take place
"If you choose this option the story end here"
Point #5b)The Events of Terminator 3:Rise of the Machines take place
"If you chose this option the story will continue"
If you choosed Point 5b this films count.
Point #6)The events of Terminator:Salavation take place.
Point #7)The the pre-Time travel scenes of Terminator:Genisys take place.
"This for the first few minutes pre Kyle Resse time travel is in cannon with the first four Terminator films than the rest will set the series for further installments back at 1"
Point #1b)Terminator 6 take place.