Here's the easiest way I can explain it..
1.) you apply for the Non-O in the US and show 3 months worth of your *actual* FDIC bank accounts showing the equivalent of 800k THB (no brokerage accounts, crypto, wallets, etc.
2.) you get your e-visa (count on at least 15 business days for it go through it's process (provided you submitted everything correctly - double check everything before you submit it), it's good for 90 days from the day you get the email... you book your flight, get your temporary residence and arrive in BKK within that 90 day period
3.) the immigration officer will stamp you in and will handwrite "Non-O" in the stamp. This is when your 90 day clock starts ticking to get things done - don't dilly-dally and wait till the last minute (I'm about to tell you why)....
4.) once you're settled in and you have your hotel, condo, pool villa, you are going to need to get a copy of your TM-30 from either the hotel management, or if you're renting, whomever you renting from - they have to submit a TM-30 application so Immigration knows where you're at.
5.) Go get your phone SIM. Take your passport to a cell provider store or kiosk (your 2 best options are AIS or True... I prefer AIS personally) as you will need this for the bank setup process).
*side note: ( I highly recommend going this route if your phone is dual sim capable).... Before I left the US, I went to my nearest T-Mobile store and ensured my existing number was set to e-sim, I then added a Tello physical SIM to my phone, set it up to use my existing US number, and then cancelled my TMobile account about a month before I moved to Thailand. The day before I flew out, I installed a Daily global esim for global data (so I could have internet access while traveling and immediately in Thailand). Then when I arrived in Thailand, I went to the AIS store and had them configure my Thai number as an esim.
6.) Take the TM-30 and your passport and head to the closest immigration office to where you're staying. The purpose of this visit is to obtain your "Residence Certificate for Bank Account", you'll go through the gauntlet and pay like 500 baht for the RC. Depending on the Immigration office, you'll also need 2 passport sized photos (most offices can take your picture on site - but I went to a photo/copy shop and got several copies to keep on hand). after you run the immigration gauntlet and get your RC, then....
7.) go to your preferred bank (i, and most others prefer Kasikorn Bank for ease of opening an account). Be sure to take your passport, tm30, residence certificate and your US drivers license). It will cost something like 300 baht for processing fees and whatever. Then, you can contact your bank back in the US and facilitate an international transfer, or transfer your 800k through wise, remitly, etc.). Now provided you didn't waste over a month to get this done, you will be well within your 2 month "seasoning" period (this means the 800k has been sitting in your Thai bank account WITHOUT GOING BELOW).
8.) Your initial 90 day visa is about to expire.. on the day you head back to immigration (with all your documents and passport), be sure to stop at your bank branch or any bank branch and get your monthly statements dating back to the day you opened the account. They will print it out for you. Take that along with all your other paperwork to Immigration. They'll look through your papers, ask you a few questions and then you'll get your 1 year extension stamp. This will cost 1900 baht if you chose a single entry stamp, or 3800 baht for multiple entry. Then you're good for a year and go back and re-extend for another year.
* as for me, i have been transferring 75k baht every month on top of my 800k sitting in the bank since month 1. I plan on after my first year is up and showing consistent deposits of over 65k/month, to then convert from keeping 800k in the back to the 65k income mode. I wouldn't play around with going below the 800k at all that first year. and if you're planning on doing the 65k route, be absolutely sure your FOREIGN deposits into the Thai bank account equal at least the 65k or more (be mindful of US and Thai holidays that can delay your transfers). I hope this helps, and good luck!