UrlLoad and UrlSave

hi, Grapesjs is a fantastic bit of software and I've been playing with it for a week or so now. Im struggling a little with the urlLoad. Im using an end point which is returning json as you can see here: How I've read the documentation, is this supposed to load the layout into the canvas? What I'm trying to do, is use the endpoints to save the canvas - and load the canvas etc. But on load nothing happens, I'm left with a blank canvas. Really appreciate if you could point me in the right direction, or a demo etc. thanks