[casinobonbiner]

when we need to see a sight or hear a sound, do we use a technique to facilitate that seeing or hearing? or does the seeing or hearing occur automatically?

I agree with you, and this is the same emphasis as my teacher Sayadaw U Tejaniya encourages. It's contrary to most techniquey techniques though and I don't think the sutta is explicit about it, rather one learns by doing, and by trial and error, and based on techniques one has learned in the past.

I think the sutta leaves a lot for interpretation and experimentation, which is why different teachers can come up with quite different techniques based on it.

[advabHixavoip]

I think the sutta leaves a lot for interpretation and experimentation

This is what I appreciate more about the suttas -in this case- Anapanasati.