Can I ask what may be a stupid question? Someone has to . . .

I haven't looked too deeply into Responsive Layout Maker yet, but while I was on this thread I thought I'd tell you what is on my mind!
Can I take a page layout already set up on my website (http://www.dabbersnantwich.me.uk as it happens) and use RLM to change that to other platforms? Or do I have to start from scratch?
If I had tried it, rather than asking a question, I might have found out by now!

You cannot import a site or the site structure into RLM, you need to start from scratch. When you have exercised a bit, it's not very hard to do. When you say 'other platforms' I take that as meaning 'other screen sizes', is that correct?

There seems to be a typo in that URL of yours, BTW. It can't be opened.