It's done digitally! I use GIMP, but pretty much any photo editor will do. It's rather simple stuff, mostly consisting of cutting and pasting. When it comes to sketching I mostly use a grid. I've explained it in more depth here, in case you want to look: ko-fi.com/s/f6bb973d7e (It's a free PDF)

How to Draw Realistic Art with Colored Pencils - BeckyKidus's Ko-fi Shop

What the title says, basically. More than 25 000 words, some 73 pages, and around a 100 example images. I've been working with colored pencils for a...