How to create a villain for level 1 players

I want to build a cool devil overlord as a villain for a group of three level 1 PCs.

How would I go about making a villain who’s more powerful than them without going overboard? Should I be scared to make it incredibly hard since there are only 3 party members? Do I make a villain like I make regular D&D characters? Or should I try and stick to the book mostly since I am new?