Things like mockups or unfinished artwork come in psd format, because of the layers. With psd format, you can transfer a file with its layers still intact and that allows you work on each individual one later on.
I got some mock ups for a book cover I designed, they were on Pinterest and they looked lovely so I downloaded them. Sadly, I couldn’t use them after I finished downloading the bulk. The file wouldn’t open when I shared it to the autodesk app. I eventually deleted all but one. Recently, I found how I could share this psd file to autodesk sketchbook, with the layers still intact. It’s quite a simple way, which I did by accident lol.
Instead of clicking on the file from your device’s file organizer, and sharing it to the app directly, go to the app instead.
Open autodesk sketchbook. You are given the option to open new sketch, new from image, new from camera , scan sketch. Pick ‘new from image’ and choose the psd file you want. Make sure you know where you saved the file. Once you click on the file, it appears on your autodesk canvases, with its layers intact.
Then I just import the image of a part of the book cover to the part of the mock up I’m working on. Say, if it is front cover, I import the front cover I made, and use the adjusters at the top of the screen, to pull on edges and get the right perspective.
Unlike apps like canva, i can’t edit the layer itself. Perhaps the good thing here is that the background, the woman holding up the book and outline of the book can be used in representing your design. The outline can be a guide.