How do you get the best transaction fees?

I have seen the mempool website linked a few times in this sub but I’m wondering how to make the best decision off of what I’m reading. I see a “Transaction Fee” section with dollar values associated with low, medium, and high Priority. Does that mean if I were to make a transaction now, at the respective priority tier, that is how much I would pay for the transaction fee? I see blocks out to ~72 minutes with much lower Sat/vB ratios, are these low priority transactions that have already been placed?

I’d appreciate any insight or documentation you could suggest that would help me understand.

Thank you!