James - Here is a link to a comprehensive listing of video tutorials that have been prepared in-house by the designers of Affinity Photo. This will also give you a better idea of what the feature set currently looks like:
https://affinity.serif.com/forum/index. ... tutorials/If you are very familiar with Photoshop, then conceptually you can pretty much sort out how things are either the same or different in AP. But it is much more intuitive & quite straight forward in its construct & operation. They are also apparently preparing a written guide due to user demand, but there are no "how-to" books that have been created that I am aware of. What is available is a PDF like file compilation of their help menus which one of the users also created & shared. (I just tried to attach it to this posting but the file extension apparently isn't allowed, so I'll track it down & find another way to get it to you.) Hope this helps.