I'm 100% on board with FI/ER concepts and plans. My SO and I have made big strides (paying off student loans, 40% SR, opening retirement vehicles, etc.)

Where I get bogged down is the details and the mechanics. I've read the sidebar, FAQs, stand alone posts, blog posts, the freaking IRS website, etc. But I still don't 'get' the mechanics. I have no idea how Mega Backdoor Roth works. I have no idea how tax loss harvesting works/when I should do it. I kind of get rebalancing. I know a SWR of 3.5% works, but I have no idea how.

For now, I've just gone with what the majority of recommendations are here.

But my lack of understanding has already cost me a couple of times this year. First, I naively opened a SEP IRA (thinking I could open an individual 401k later this year. I can't). Second, I've naively contributed 20% to the SEP IRA (thinking I could still take advantage of the FEIE up to the allowable amount. I can't.).

I'm worried this lack of understanding will lead to larger problems down the road — especially as I figure out where to put the rest of our 40% SR.

Is anyone else in my shoes? How did you start wrapping your head around the details and making smarter decisions?