Once you submit the application a QR code is generated, it's a little tricky to find in the portal, you download and print that QR code and take it to the Embassy the next morning 9:00 a.m. and pay, you will not get in without the QR code. Tomorrow is a Thai national holiday so likely it's closed.
You need to be in the area that the embassy has jurisdiction over for the submission of the application, after that you can travel around the country but be aware you can be called in for an interview, and Vietnam usually asks for a very specific proof of location.
just because you're not doing it, doesn't mean you're following the rules. The TM30 is to be filed every time a foreigner takes up accommodation no matter who owns it. If you ever need services from your local immigration office, welcome to the wake up call.