What is the next step after submitting documents for a Thai LTR visa?

You must go to the BOI office in Bangkok if applying within Thailand.

it takes about 4-5 weeks so just wait

If OK with the LTR unit, they will issue you an endorsement document which means that you have satisfied the requirements. With that, you then make an appointment with them within the 60 days of the endorsement letter. On the appointment day, you go to their office in Bangkok with the required signed documents (they will let you know what). They will assign a staff person to go over the documents. Once that is done, you go for a photograph. Your documents and passport are sent across the hall to immigration for processing. The LTR staff member will get you after immigration has OKed the documents and bring you to immigration where you will pay the 50,000 THB and get a receipt.. From there you will go to the special LTR Window in immigration for a photograph and show the receipt.. They will then process the visa. They will call you to the window and show you the visa for 2034, entry until 2029, multiple entry stamp, and 1 year reporting note stapled to your passport. You go back across the hall to the LTR unit where the assigned staff member will review your passport to ensure the correct visa, entry date, multiple entry stamp, and 1 year reporting note.