Can someone please explain function pairings and function pairs?

I’m a bit confused about this.

So I’m watching a CPT video about how functions come in pairs in terms of perceiving and judging.

Perceiving: Ne, Ni, Se, Si Judging: Te, Ti, Fe, Fi

Example — for ENFP, this would be Ne-Te, then Fi-Si. And if I’m understanding it correctly extroverted functions are the pilot, whereas Fi-Si are the copilot.

But then how does function pair theory fit into this?

Example — for ENFP, this would be Ne-Si, and Fi-Te.

I’m legit confused now am I missing a link here?

Can someone pls help I can’t move forward with researching this stuff till I’ve understood this 🙏