Ok, good the requirements varies but this is normally the general requirements I guess. Some accept a affidavit letter and some don’t too, and it’s of course always recommended to get handed over the specific requirement at your immigration first.
You can apply directly for a 90 days Non O based on marriage and the financial requirements are 400K baht in a Thai bank at date when you apply.
Within 90 days you can apply for your first year extension of stay (as several people names one year visa) and the funds needs to be seasoned for two months prior to your application.