I am an absolute beginner to drawing software and mapmaking, and I'm looking to get started by making some alternate history maps. It seems like the easiest way to get started would be to import real-world maps with only continental boundaries, or possibly with editable political boundaries, but I don't have any idea how to go about this, and haven't found anything in the tutorials or older forum threads about it.

Any advice, or just pointing me somewhere else this is addressed, would be greatly appreciated.