I feel dumb, but I don’t understand how to do ekko charge s2 in combos

So I see lots of combos that people have done on me, and in tournament videos but I never understood how would you do the charged s2 in combo? I feel like by the time it’s charged, the enemy flips out.

Is there a basic combo that uses charge s2? Or is charge s2 only used in later parts of his combos?