Understand what it is and how it works (in theory). I'm wondering how do I physically utilize those nodes in that picture to my advantage right now?
The nodes are there to facilitate a payment of an invoice. You don't directly utilize them, per se.
AFAIK, if you want to send a payment for
n sat from Sender A to Receiver B, it needs to get routed through nodes with sufficient funding.
It's sort of like TOR, but for small Bitcorn transactions.