Original Timeline= Everything as normal till Judgement Day, John sends Kyle back in time to protect Sarah from a T-800.
Timeline 1(T1)= Kyle is sent back in time, changing events where parts of the T-800 are found leading to Skynet's advancement in the T-1000 being sent back to kill John.
Timeline 2(T2)= John sends back a reprogrammed T-800 to protect his younger self, the Cyberdyne building is destroyed and all it's work, thus postponing Judgement Day.
Timeline 3(T3)= John goes off the grid, cannot be found by Skynet, military bought the assets of Cyberdyne to create the Hunter Killers, T-1 and Skynet(as well as the T-X later on in the future). Skynet gets activated and starts to rebel.
Timeline 4(T:S)= Marcus Wright becomes the prototype Infiltration model for the T-800, one year later before Skynet's activation, which is then noted by John later in 2018 to be further along in production of the 800s.
Timeline 5(T:G)= All the previous timelines get re-written/overhauled into this new timeline.