if there's a next time, youtube videos will often help you find an answer to just about anything. And without wishing to sound rude, brush up your skills, thailand is IT and phone dependent for much of life. Took me quite a while to master ordering my dinner in a restaurant with a QR code!
took me less than 15 minutes. Google docs is your friend. Creat a blank document. Insert images. Resize images click and drag, to fit two to a page. Download as pdf. Upload to visa site.
if your application is based on retirement...you need to prove 800k in your currency has been in a bank account in your name only for three months, so 3 consecutive bank statements. You'll need to put 3 statements in to one document. You can only upload one document up to 3mb. I used Google docs, pasted in each statement as an image file, downloaded as a pdf to my PC and uploaded that to the visa application