If you are technical you can understand the concepts of invoices and integrating lightning into an application fairly easily through calling endpoints on a lightning node. This course looks pretty good for that type of thing: https://www.udemy.com/course/pleblabaustin/. If you really want to understand lightning actually works, I would first suggest trying to get a solid understanding of how bitcoin works with Andreas' book: https://github.com/bitcoinbook/bitcoinbook. Just note that the ecosystem is huge and there is a lot of stuff to learn but any progress is worth it.