How do you start a ms 260 stihl properly?

The first part of the answer is safely. Place the saw on a stable surface, squeeze the interlock/trigger in, move control bar (left of the handle) all the way down, brace your left arm/hand against the upper handle, right toe/foot it the back handle, grasp the grip and ease out until you a sharp resistance and then tug sharply. On a cold engine it may take a few pulls. The engine will "flutter" and then move the control bar up one notch. Repeat until engine fires and revs and squeeze trigger to bring it back to the idle position